src/Pure/Concurrent/future.ML
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(*  Title:      Pure/Concurrent/future.ML
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    Author:     Makarius
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Value-oriented parallelism via futures and promises.  See also
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http://www4.in.tum.de/~wenzelm/papers/parallel-isabelle.pdf
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http://www4.in.tum.de/~wenzelm/papers/parallel-ml.pdf
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Notes:
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  * Futures are similar to delayed evaluation, i.e. delay/force is
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    generalized to fork/join.  The idea is to model parallel
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    value-oriented computations (not communicating processes).
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  * Forked futures are evaluated spontaneously by a farm of worker
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    threads in the background; join resynchronizes the computation and
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    delivers results (values or exceptions).
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  * The pool of worker threads is limited, usually in correlation with
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    the number of physical cores on the machine.  Note that allocation
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    of runtime resources may be distorted either if workers yield CPU
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    time (e.g. via system sleep or wait operations), or if non-worker
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    threads contend for significant runtime resources independently.
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    There is a limited number of replacement worker threads that get
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    activated in certain explicit wait conditions.
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  * Future tasks are organized in groups, which are block-structured.
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    When forking a new new task, the default is to open an individual
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    subgroup, unless some common group is specified explicitly.
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    Failure of one group member causes peer and subgroup members to be
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    interrupted eventually.  Interrupted tasks that lack regular
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    result information, will pick up parallel exceptions from the
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    cumulative group context (as Par_Exn).
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  * Future task groups may be canceled: present and future group
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    members will be interrupted eventually.
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  * Promised "passive" futures are fulfilled by external means.  There
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    is no associated evaluation task, but other futures can depend on
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    them via regular join operations.
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*)
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signature FUTURE =
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sig
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  type task = Task_Queue.task
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  type group = Task_Queue.group
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  val new_group: group option -> group
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  val worker_task: unit -> task option
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  val worker_group: unit -> group option
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  val the_worker_group: unit -> group
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  val worker_subgroup: unit -> group
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  val worker_nest: string -> ('a -> 'b) -> 'a -> 'b
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  val worker_guest: string -> group -> ('a -> 'b) -> 'a -> 'b
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  type 'a future
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  val task_of: 'a future -> task
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  val peek: 'a future -> 'a Exn.result option
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  val is_finished: 'a future -> bool
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  val ML_statistics: bool Unsynchronized.ref
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  val interruptible_task: ('a -> 'b) -> 'a -> 'b
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  val cancel_group: group -> unit
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  val cancel: 'a future -> unit
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  val error_msg: Position.T -> (serial * string) * string option -> unit
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  val identify_result: Position.T -> 'a Exn.result -> 'a Exn.result
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  type params = {name: string, group: group option, deps: task list, pri: int, interrupts: bool}
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  val default_params: params
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  val forks: params -> (unit -> 'a) list -> 'a future list
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  val fork: (unit -> 'a) -> 'a future
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  val join_results: 'a future list -> 'a Exn.result list
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  val join_result: 'a future -> 'a Exn.result
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  val joins: 'a future list -> 'a list
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  val join: 'a future -> 'a
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  val join_tasks: task list -> unit
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  val value_result: 'a Exn.result -> 'a future
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  val value: 'a -> 'a future
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  val cond_forks: params -> (unit -> 'a) list -> 'a future list
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  val map: ('a -> 'b) -> 'a future -> 'b future
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  val promise_group: group -> (unit -> unit) -> 'a future
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  val promise: (unit -> unit) -> 'a future
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  val fulfill_result: 'a future -> 'a Exn.result -> unit
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  val fulfill: 'a future -> 'a -> unit
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  val group_snapshot: group -> task list
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  val terminate: group -> unit
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  val shutdown: unit -> unit
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end;
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structure Future: FUTURE =
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struct
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(** future values **)
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type task = Task_Queue.task;
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type group = Task_Queue.group;
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val new_group = Task_Queue.new_group;
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(* identifiers *)
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local
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  val tag = Universal.tag () : task option Universal.tag;
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in
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  fun worker_task () = the_default NONE (Thread.getLocal tag);
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  fun setmp_worker_task task f x = setmp_thread_data tag (worker_task ()) (SOME task) f x;
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end;
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val worker_group = Option.map Task_Queue.group_of_task o worker_task;
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fun the_worker_group () =
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  (case worker_group () of
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    SOME group => group
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  | NONE => raise Fail "Missing worker thread context");
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fun worker_subgroup () = new_group (worker_group ());
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fun worker_nest name f x =
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  setmp_worker_task (Task_Queue.new_task (the_worker_group ()) name NONE) f x;
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fun worker_guest name group f x =
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  if is_some (worker_task ()) then
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    raise Fail "Already running as worker thread"
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  else setmp_worker_task (Task_Queue.new_task group name NONE) f x;
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fun worker_joining e =
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  (case worker_task () of
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    NONE => e ()
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  | SOME task => Task_Queue.joining task e);
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fun worker_waiting deps e =
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  (case worker_task () of
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    NONE => e ()
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  | SOME task => Task_Queue.waiting task deps e);
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(* datatype future *)
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type 'a result = 'a Exn.result Single_Assignment.var;
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datatype 'a future = Future of
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 {promised: bool,
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  task: task,
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  result: 'a result};
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fun task_of (Future {task, ...}) = task;
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fun result_of (Future {result, ...}) = result;
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fun peek x = Single_Assignment.peek (result_of x);
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fun is_finished x = is_some (peek x);
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(** scheduling **)
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(* synchronization *)
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val scheduler_event = ConditionVar.conditionVar ();
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val work_available = ConditionVar.conditionVar ();
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val work_finished = ConditionVar.conditionVar ();
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local
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  val lock = Mutex.mutex ();
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in
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fun SYNCHRONIZED name = Simple_Thread.synchronized name lock;
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fun wait cond = (*requires SYNCHRONIZED*)
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  Multithreading.sync_wait NONE NONE cond lock;
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fun wait_timeout timeout cond = (*requires SYNCHRONIZED*)
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  Multithreading.sync_wait NONE (SOME (Time.+ (Time.now (), timeout))) cond lock;
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fun signal cond = (*requires SYNCHRONIZED*)
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  ConditionVar.signal cond;
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fun broadcast cond = (*requires SYNCHRONIZED*)
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  ConditionVar.broadcast cond;
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end;
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(* global state *)
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val queue = Unsynchronized.ref Task_Queue.empty;
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val next = Unsynchronized.ref 0;
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val scheduler = Unsynchronized.ref (NONE: Thread.thread option);
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val canceled = Unsynchronized.ref ([]: group list);
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val do_shutdown = Unsynchronized.ref false;
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val max_workers = Unsynchronized.ref 0;
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val max_active = Unsynchronized.ref 0;
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val worker_trend = Unsynchronized.ref 0;
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val status_ticks = Unsynchronized.ref 0;
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val last_round = Unsynchronized.ref Time.zeroTime;
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val next_round = seconds 0.05;
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datatype worker_state = Working | Waiting | Sleeping;
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val workers = Unsynchronized.ref ([]: (Thread.thread * worker_state Unsynchronized.ref) list);
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fun count_workers state = (*requires SYNCHRONIZED*)
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  fold (fn (_, state_ref) => fn i => if ! state_ref = state then i + 1 else i) (! workers) 0;
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(* status *)
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val ML_statistics = Unsynchronized.ref false;
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fun report_status () = (*requires SYNCHRONIZED*)
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  if ! ML_statistics then
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    let
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      val {ready, pending, running, passive} = Task_Queue.status (! queue);
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      val total = length (! workers);
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      val active = count_workers Working;
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      val waiting = count_workers Waiting;
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      val stats =
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       [("now", Markup.print_real (Time.toReal (Time.now ()))),
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        ("tasks_ready", Markup.print_int ready),
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        ("tasks_pending", Markup.print_int pending),
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        ("tasks_running", Markup.print_int running),
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        ("tasks_passive", Markup.print_int passive),
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        ("workers_total", Markup.print_int total),
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        ("workers_active", Markup.print_int active),
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        ("workers_waiting", Markup.print_int waiting)] @
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        ML_Statistics.get ();
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    in Output.try_protocol_message (Markup.ML_statistics :: stats) "" end
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  else ();
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(* cancellation primitives *)
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fun cancel_now group = (*requires SYNCHRONIZED*)
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  let
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    val running = Task_Queue.cancel (! queue) group;
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    val _ = running |> List.app (fn thread =>
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      if Simple_Thread.is_self thread then ()
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      else Simple_Thread.interrupt_unsynchronized thread);
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  in running end;
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fun cancel_all () = (*requires SYNCHRONIZED*)
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  let
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    val (groups, threads) = Task_Queue.cancel_all (! queue);
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    val _ = List.app Simple_Thread.interrupt_unsynchronized threads;
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  in groups end;
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fun cancel_later group = (*requires SYNCHRONIZED*)
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 (Unsynchronized.change canceled (insert Task_Queue.eq_group group);
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  broadcast scheduler_event);
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fun interruptible_task f x =
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  (if Multithreading.available then
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    Multithreading.with_attributes
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      (if is_some (worker_task ())
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       then Multithreading.private_interrupts
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       else Multithreading.public_interrupts)
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      (fn _ => f x)
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   else interruptible f x)
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  before Multithreading.interrupted ();
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(* worker threads *)
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fun worker_exec (task, jobs) =
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  let
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    val group = Task_Queue.group_of_task task;
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    val valid = not (Task_Queue.is_canceled group);
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    val ok =
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      Task_Queue.running task (fn () =>
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        setmp_worker_task task (fn () =>
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          fold (fn job => fn ok => job valid andalso ok) jobs true) ());
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    val _ =
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      if ! Multithreading.trace >= 2 then
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        Output.try_protocol_message (Markup.task_statistics :: Task_Queue.task_statistics task) ""
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      else ();
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    val _ = SYNCHRONIZED "finish" (fn () =>
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      let
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        val maximal = Unsynchronized.change_result queue (Task_Queue.finish task);
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        val test = Exn.capture Multithreading.interrupted ();
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        val _ =
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          if ok andalso not (Exn.is_interrupt_exn test) then ()
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          else if null (cancel_now group) then ()
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          else cancel_later group;
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        val _ = broadcast work_finished;
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        val _ = if maximal then () else signal work_available;
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      in () end);
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  in () end;
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fun worker_wait active cond = (*requires SYNCHRONIZED*)
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  (case AList.lookup Thread.equal (! workers) (Thread.self ()) of
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    SOME state =>
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     (state := (if active then Waiting else Sleeping);
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      wait cond;
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      state := Working)
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  | NONE => ignore (wait cond));
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fun worker_next () = (*requires SYNCHRONIZED*)
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  if length (! workers) > ! max_workers then
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    (Unsynchronized.change workers (AList.delete Thread.equal (Thread.self ()));
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     signal work_available;
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     NONE)
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  else if count_workers Working > ! max_active then
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    (worker_wait false work_available; worker_next ())
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  else
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    (case Unsynchronized.change_result queue (Task_Queue.dequeue (Thread.self ())) of
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      NONE => (worker_wait false work_available; worker_next ())
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    | some => (signal work_available; some));
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fun worker_loop name =
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  (case SYNCHRONIZED name (fn () => worker_next ()) of
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   306
    NONE => ()
44295
e43f0ea90c9a more focused use of Multithreading.interrupted: retain interrupts within task group boundary, without loss of information;
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   307
  | SOME work => (worker_exec work; worker_loop name));
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   308
33407
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   309
fun worker_start name = (*requires SYNCHRONIZED*)
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3165bc303f66 modernized some structure names, keeping a few legacy aliases;
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   310
  Unsynchronized.change workers (cons (Simple_Thread.fork false (fn () => worker_loop name),
33410
e351f4c1f18c worker activity: distinguish between waiting (formerly active) and sleeping;
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diff changeset
   311
    Unsynchronized.ref Working));
28156
5205f7979b4f Functional threads as future values.
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parents:
diff changeset
   312
5205f7979b4f Functional threads as future values.
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parents:
diff changeset
   313
5205f7979b4f Functional threads as future values.
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parents:
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   314
(* scheduler *)
5205f7979b4f Functional threads as future values.
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diff changeset
   315
28206
bcd48c6897d4 eliminated requests, use global state variables uniformly;
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   316
fun scheduler_next () = (*requires SYNCHRONIZED*)
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5205f7979b4f Functional threads as future values.
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diff changeset
   317
  let
33407
1427333220bc worker_next: ensure that work_available is passed on before sleeping (was occasionally lost when worker configuration changed, causing scheduler deadlock);
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diff changeset
   318
    val now = Time.now ();
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diff changeset
   319
    val tick = Time.<= (Time.+ (! last_round, next_round), now);
1427333220bc worker_next: ensure that work_available is passed on before sleeping (was occasionally lost when worker configuration changed, causing scheduler deadlock);
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diff changeset
   320
    val _ = if tick then last_round := now else ();
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diff changeset
   321
33415
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parents: 33413
diff changeset
   322
50280
0eb9b5d09f31 more uniform ML statistics;
wenzelm
parents: 50255
diff changeset
   323
    (* runtime status *)
33415
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
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parents: 33413
diff changeset
   324
32226
23511e4da055 tuned tracing;
wenzelm
parents: 32225
diff changeset
   325
    val _ =
51046
26a0984191b3 report status more frequently on demand;
wenzelm
parents: 50983
diff changeset
   326
      if tick then Unsynchronized.change status_ticks (fn i => i + 1) else ();
33407
1427333220bc worker_next: ensure that work_available is passed on before sleeping (was occasionally lost when worker configuration changed, causing scheduler deadlock);
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diff changeset
   327
    val _ =
51046
26a0984191b3 report status more frequently on demand;
wenzelm
parents: 50983
diff changeset
   328
      if tick andalso ! status_ticks mod (if ! Multithreading.trace >= 1 then 2 else 10) = 0
26a0984191b3 report status more frequently on demand;
wenzelm
parents: 50983
diff changeset
   329
      then report_status () else ();
32053
257eac3946e9 scheduler: tuned tracing (status);
wenzelm
parents: 31631
diff changeset
   330
28191
9e5f556409c6 future: allow explicit group;
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parents: 28186
diff changeset
   331
    val _ =
32219
9a2566d1fdbd more specific conditions: scheduler_event, work_available, work_finished -- considereably reduces overhead with many threads;
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parents: 32186
diff changeset
   332
      if forall (Thread.isActive o #1) (! workers) then ()
32095
ad4be204fdfe tuned tracing;
wenzelm
parents: 32058
diff changeset
   333
      else
33409
wenzelm
parents: 33408
diff changeset
   334
        let
37682
ad5489a6be48 tuned white space;
wenzelm
parents: 37216
diff changeset
   335
          val (alive, dead) = List.partition (Thread.isActive o #1) (! workers);
33409
wenzelm
parents: 33408
diff changeset
   336
          val _ = workers := alive;
wenzelm
parents: 33408
diff changeset
   337
        in
wenzelm
parents: 33408
diff changeset
   338
          Multithreading.tracing 0 (fn () =>
51279
f4a2fa9286e9 tuned messages;
wenzelm
parents: 51046
diff changeset
   339
            "SCHEDULER: disposed " ^ string_of_int (length dead) ^ " dead worker threads")
33409
wenzelm
parents: 33408
diff changeset
   340
        end;
28191
9e5f556409c6 future: allow explicit group;
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parents: 28186
diff changeset
   341
33415
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
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parents: 33413
diff changeset
   342
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
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parents: 33413
diff changeset
   343
    (* worker pool adjustments *)
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
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   344
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
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parents: 33413
diff changeset
   345
    val max_active0 = ! max_active;
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
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parents: 33413
diff changeset
   346
    val max_workers0 = ! max_workers;
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
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parents: 33413
diff changeset
   347
28206
bcd48c6897d4 eliminated requests, use global state variables uniformly;
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parents: 28203
diff changeset
   348
    val m = if ! do_shutdown then 0 else Multithreading.max_threads_value ();
33406
1ddcb8472bd2 slightly leaner and more direct control of worker activity etc.;
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parents: 33061
diff changeset
   349
    val _ = max_active := m;
1ddcb8472bd2 slightly leaner and more direct control of worker activity etc.;
wenzelm
parents: 33061
diff changeset
   350
33411
a07558eb5029 worker_next: treat wait for work_available as Sleeping, not Waiting;
wenzelm
parents: 33410
diff changeset
   351
    val mm =
a07558eb5029 worker_next: treat wait for work_available as Sleeping, not Waiting;
wenzelm
parents: 33410
diff changeset
   352
      if ! do_shutdown then 0
33413
cb409680dda8 avoid broadcast work_available, use daisy-chained signal instead;
wenzelm
parents: 33411
diff changeset
   353
      else Int.min (Int.max (count_workers Working + 2 * count_workers Waiting, m), 4 * m);
33411
a07558eb5029 worker_next: treat wait for work_available as Sleeping, not Waiting;
wenzelm
parents: 33410
diff changeset
   354
    val _ =
a07558eb5029 worker_next: treat wait for work_available as Sleeping, not Waiting;
wenzelm
parents: 33410
diff changeset
   355
      if tick andalso mm > ! max_workers then
a07558eb5029 worker_next: treat wait for work_available as Sleeping, not Waiting;
wenzelm
parents: 33410
diff changeset
   356
        Unsynchronized.change worker_trend (fn w => if w < 0 then 0 else w + 1)
a07558eb5029 worker_next: treat wait for work_available as Sleeping, not Waiting;
wenzelm
parents: 33410
diff changeset
   357
      else if tick andalso mm < ! max_workers then
a07558eb5029 worker_next: treat wait for work_available as Sleeping, not Waiting;
wenzelm
parents: 33410
diff changeset
   358
        Unsynchronized.change worker_trend (fn w => if w > 0 then 0 else w - 1)
a07558eb5029 worker_next: treat wait for work_available as Sleeping, not Waiting;
wenzelm
parents: 33410
diff changeset
   359
      else ();
a07558eb5029 worker_next: treat wait for work_available as Sleeping, not Waiting;
wenzelm
parents: 33410
diff changeset
   360
    val _ =
33415
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   361
      if mm = 0 orelse ! worker_trend > 50 orelse ! worker_trend < ~50 then
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   362
        max_workers := mm
44173
aaaa13e297dc immediate fork of initial workers -- avoid 5 ticks (250ms) for adaptive scheme (a07558eb5029);
wenzelm
parents: 44115
diff changeset
   363
      else if ! worker_trend > 5 andalso ! max_workers < 2 * m orelse ! max_workers = 0 then
33415
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   364
        max_workers := Int.min (mm, 2 * m)
33411
a07558eb5029 worker_next: treat wait for work_available as Sleeping, not Waiting;
wenzelm
parents: 33410
diff changeset
   365
      else ();
33406
1ddcb8472bd2 slightly leaner and more direct control of worker activity etc.;
wenzelm
parents: 33061
diff changeset
   366
33407
1427333220bc worker_next: ensure that work_available is passed on before sleeping (was occasionally lost when worker configuration changed, causing scheduler deadlock);
wenzelm
parents: 33406
diff changeset
   367
    val missing = ! max_workers - length (! workers);
28203
88f18387f1c9 shutdown: global join-and-shutdown operation;
wenzelm
parents: 28202
diff changeset
   368
    val _ =
33407
1427333220bc worker_next: ensure that work_available is passed on before sleeping (was occasionally lost when worker configuration changed, causing scheduler deadlock);
wenzelm
parents: 33406
diff changeset
   369
      if missing > 0 then
33415
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   370
        funpow missing (fn () =>
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   371
          ignore (worker_start ("worker " ^ string_of_int (Unsynchronized.inc next)))) ()
28203
88f18387f1c9 shutdown: global join-and-shutdown operation;
wenzelm
parents: 28202
diff changeset
   372
      else ();
28206
bcd48c6897d4 eliminated requests, use global state variables uniformly;
wenzelm
parents: 28203
diff changeset
   373
33415
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   374
    val _ =
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   375
      if ! max_active = max_active0 andalso ! max_workers = max_workers0 then ()
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   376
      else signal work_available;
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   377
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   378
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   379
    (* canceled groups *)
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   380
32225
d5d6f47fb018 cancel: improved reactivity due to more careful broadcasting;
wenzelm
parents: 32224
diff changeset
   381
    val _ =
d5d6f47fb018 cancel: improved reactivity due to more careful broadcasting;
wenzelm
parents: 32224
diff changeset
   382
      if null (! canceled) then ()
32293
e0b8da3fae4d tuned tracing;
wenzelm
parents: 32286
diff changeset
   383
      else
e0b8da3fae4d tuned tracing;
wenzelm
parents: 32286
diff changeset
   384
       (Multithreading.tracing 1 (fn () =>
e0b8da3fae4d tuned tracing;
wenzelm
parents: 32286
diff changeset
   385
          string_of_int (length (! canceled)) ^ " canceled groups");
44299
061599cb6eb0 refined Future.cancel: explicit future allows to join actual cancellation;
wenzelm
parents: 44298
diff changeset
   386
        Unsynchronized.change canceled (filter_out (null o cancel_now));
51281
c05f7e1dd602 signal work_available should be sufficient to initiate daisy-chained workers, and lead to separate broadcast work_finished eventually -- NB: broadcasting all worker threads tends to burn parallel CPU cycles;
wenzelm
parents: 51280
diff changeset
   387
        signal work_available);
28206
bcd48c6897d4 eliminated requests, use global state variables uniformly;
wenzelm
parents: 28203
diff changeset
   388
33415
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   389
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   390
    (* delay loop *)
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   391
32295
400cc493d466 renamed Multithreading.regular_interrupts to Multithreading.public_interrupts;
wenzelm
parents: 32293
diff changeset
   392
    val _ = Exn.release (wait_timeout next_round scheduler_event);
28167
27e2ca41b58c more interrupt operations;
wenzelm
parents: 28166
diff changeset
   393
33415
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   394
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   395
    (* shutdown *)
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   396
34277
7325a5e3587f added Future.promise/fulfill -- promised futures that are fulfilled by external means;
wenzelm
parents: 33416
diff changeset
   397
    val _ = if Task_Queue.all_passive (! queue) then do_shutdown := true else ();
32219
9a2566d1fdbd more specific conditions: scheduler_event, work_available, work_finished -- considereably reduces overhead with many threads;
wenzelm
parents: 32186
diff changeset
   398
    val continue = not (! do_shutdown andalso null (! workers));
50429
f8cd5e53653b final report_status within SYNCHRONIZED part of scheduler loop: required for sanity of data;
wenzelm
parents: 50280
diff changeset
   399
    val _ = if continue then () else (report_status (); scheduler := NONE);
33415
352fe8e9162d worker_next: plain signalling via work_available only, not scheduler_event;
wenzelm
parents: 33413
diff changeset
   400
32219
9a2566d1fdbd more specific conditions: scheduler_event, work_available, work_finished -- considereably reduces overhead with many threads;
wenzelm
parents: 32186
diff changeset
   401
    val _ = broadcast scheduler_event;
32295
400cc493d466 renamed Multithreading.regular_interrupts to Multithreading.public_interrupts;
wenzelm
parents: 32293
diff changeset
   402
  in continue end
39232
69c6d3e87660 more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents: 38236
diff changeset
   403
  handle exn =>
69c6d3e87660 more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents: 38236
diff changeset
   404
    if Exn.is_interrupt exn then
51279
f4a2fa9286e9 tuned messages;
wenzelm
parents: 51046
diff changeset
   405
     (Multithreading.tracing 1 (fn () => "SCHEDULER: Interrupt");
44341
a93d25fb14fc purely functional task_queue.ML -- moved actual interrupt_unsynchronized to future.ML;
wenzelm
parents: 44330
diff changeset
   406
      List.app cancel_later (cancel_all ());
51281
c05f7e1dd602 signal work_available should be sufficient to initiate daisy-chained workers, and lead to separate broadcast work_finished eventually -- NB: broadcasting all worker threads tends to burn parallel CPU cycles;
wenzelm
parents: 51280
diff changeset
   407
      signal work_available; true)
39232
69c6d3e87660 more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents: 38236
diff changeset
   408
    else reraise exn;
32295
400cc493d466 renamed Multithreading.regular_interrupts to Multithreading.public_interrupts;
wenzelm
parents: 32293
diff changeset
   409
28206
bcd48c6897d4 eliminated requests, use global state variables uniformly;
wenzelm
parents: 28203
diff changeset
   410
fun scheduler_loop () =
44173
aaaa13e297dc immediate fork of initial workers -- avoid 5 ticks (250ms) for adaptive scheme (a07558eb5029);
wenzelm
parents: 44115
diff changeset
   411
 (while
33416
13d00799fe49 scheduler: clarified interrupt attributes and handling;
wenzelm
parents: 33415
diff changeset
   412
    Multithreading.with_attributes
13d00799fe49 scheduler: clarified interrupt attributes and handling;
wenzelm
parents: 33415
diff changeset
   413
      (Multithreading.sync_interrupts Multithreading.public_interrupts)
13d00799fe49 scheduler: clarified interrupt attributes and handling;
wenzelm
parents: 33415
diff changeset
   414
      (fn _ => SYNCHRONIZED "scheduler" (fn () => scheduler_next ()))
50429
f8cd5e53653b final report_status within SYNCHRONIZED part of scheduler loop: required for sanity of data;
wenzelm
parents: 50280
diff changeset
   415
  do (); last_round := Time.zeroTime);
28156
5205f7979b4f Functional threads as future values.
wenzelm
parents:
diff changeset
   416
28203
88f18387f1c9 shutdown: global join-and-shutdown operation;
wenzelm
parents: 28202
diff changeset
   417
fun scheduler_active () = (*requires SYNCHRONIZED*)
88f18387f1c9 shutdown: global join-and-shutdown operation;
wenzelm
parents: 28202
diff changeset
   418
  (case ! scheduler of NONE => false | SOME thread => Thread.isActive thread);
88f18387f1c9 shutdown: global join-and-shutdown operation;
wenzelm
parents: 28202
diff changeset
   419
32228
7622c03141b0 scheduler: shutdown spontaneously (after some delay) if queue is empty;
wenzelm
parents: 32227
diff changeset
   420
fun scheduler_check () = (*requires SYNCHRONIZED*)
7622c03141b0 scheduler: shutdown spontaneously (after some delay) if queue is empty;
wenzelm
parents: 32227
diff changeset
   421
 (do_shutdown := false;
32248
0241916a5f06 more precise treatment of scheduler_event: continous pulse (50ms) instead of flooding, which was burning many CPU cycles in spare threads;
wenzelm
parents: 32247
diff changeset
   422
  if scheduler_active () then ()
37216
3165bc303f66 modernized some structure names, keeping a few legacy aliases;
wenzelm
parents: 37182
diff changeset
   423
  else scheduler := SOME (Simple_Thread.fork false scheduler_loop));
28156
5205f7979b4f Functional threads as future values.
wenzelm
parents:
diff changeset
   424
44301
65f60d9ac4bf tuned signature (again);
wenzelm
parents: 44300
diff changeset
   425
65f60d9ac4bf tuned signature (again);
wenzelm
parents: 44300
diff changeset
   426
65f60d9ac4bf tuned signature (again);
wenzelm
parents: 44300
diff changeset
   427
(** futures **)
65f60d9ac4bf tuned signature (again);
wenzelm
parents: 44300
diff changeset
   428
65f60d9ac4bf tuned signature (again);
wenzelm
parents: 44300
diff changeset
   429
(* cancel *)
65f60d9ac4bf tuned signature (again);
wenzelm
parents: 44300
diff changeset
   430
49906
06a3570b0f0a more official Future.terminate;
wenzelm
parents: 49894
diff changeset
   431
fun cancel_group_unsynchronized group = (*requires SYNCHRONIZED*)
44299
061599cb6eb0 refined Future.cancel: explicit future allows to join actual cancellation;
wenzelm
parents: 44298
diff changeset
   432
  let
47421
9624408d8827 always signal after cancel_group: passive tasks may have become active;
wenzelm
parents: 47404
diff changeset
   433
    val _ = if null (cancel_now group) then () else cancel_later group;
9624408d8827 always signal after cancel_group: passive tasks may have become active;
wenzelm
parents: 47404
diff changeset
   434
    val _ = signal work_available;
9624408d8827 always signal after cancel_group: passive tasks may have become active;
wenzelm
parents: 47404
diff changeset
   435
    val _ = scheduler_check ();
49906
06a3570b0f0a more official Future.terminate;
wenzelm
parents: 49894
diff changeset
   436
  in () end;
06a3570b0f0a more official Future.terminate;
wenzelm
parents: 49894
diff changeset
   437
06a3570b0f0a more official Future.terminate;
wenzelm
parents: 49894
diff changeset
   438
fun cancel_group group =
06a3570b0f0a more official Future.terminate;
wenzelm
parents: 49894
diff changeset
   439
  SYNCHRONIZED "cancel_group" (fn () => cancel_group_unsynchronized group);
44299
061599cb6eb0 refined Future.cancel: explicit future allows to join actual cancellation;
wenzelm
parents: 44298
diff changeset
   440
44301
65f60d9ac4bf tuned signature (again);
wenzelm
parents: 44300
diff changeset
   441
fun cancel x = cancel_group (Task_Queue.group_of_task (task_of x));
29366
1ffc8cbf39ec tuned map: reduced overhead due to bulk jobs;
wenzelm
parents: 29341
diff changeset
   442
28156
5205f7979b4f Functional threads as future values.
wenzelm
parents:
diff changeset
   443
50914
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   444
(* results *)
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   445
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   446
fun error_msg pos ((serial, msg), exec_id) =
50916
fd902b616b48 proper runtime position (cf. fe4714886d92 and Toplevel.error_msg) -- to make error messages actually appear in the document;
wenzelm
parents: 50914
diff changeset
   447
  Position.setmp_thread_data pos (fn () =>
50931
a7484a7b6c8a clarified Future.error_msg: slightly more robust id check, actually suppress displaced messages;
wenzelm
parents: 50916
diff changeset
   448
    let val id = Position.get_id pos in
a7484a7b6c8a clarified Future.error_msg: slightly more robust id check, actually suppress displaced messages;
wenzelm
parents: 50916
diff changeset
   449
      if is_none id orelse is_none exec_id orelse id = exec_id
a7484a7b6c8a clarified Future.error_msg: slightly more robust id check, actually suppress displaced messages;
wenzelm
parents: 50916
diff changeset
   450
      then Output.error_msg' (serial, msg) else ()
a7484a7b6c8a clarified Future.error_msg: slightly more robust id check, actually suppress displaced messages;
wenzelm
parents: 50916
diff changeset
   451
    end) ();
44110
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   452
50914
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   453
fun identify_result pos res =
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   454
  (case res of
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   455
    Exn.Exn exn =>
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   456
      let val exec_id =
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   457
        (case Position.get_id pos of
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   458
          NONE => []
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   459
        | SOME id => [(Markup.exec_idN, id)])
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   460
      in Exn.Exn (Par_Exn.identify exec_id exn) end
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   461
  | _ => res);
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   462
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   463
fun assign_result group result res =
44110
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   464
  let
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   465
    val _ = Single_Assignment.assign result res
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   466
      handle exn as Fail _ =>
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   467
        (case Single_Assignment.peek result of
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   468
          SOME (Exn.Exn e) => reraise (if Exn.is_interrupt e then e else exn)
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   469
        | _ => reraise exn);
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   470
    val ok =
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   471
      (case the (Single_Assignment.peek result) of
44111
2d16c693d536 synchronized cancel and flushing of Multithreading.interrupted state, to ensure that interrupts stay within task boundaries;
wenzelm
parents: 44110
diff changeset
   472
        Exn.Exn exn =>
2d16c693d536 synchronized cancel and flushing of Multithreading.interrupted state, to ensure that interrupts stay within task boundaries;
wenzelm
parents: 44110
diff changeset
   473
          (SYNCHRONIZED "cancel" (fn () => Task_Queue.cancel_group group exn); false)
44110
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   474
      | Exn.Res _ => true);
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   475
  in ok end;
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   476
50914
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   477
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   478
(* future jobs *)
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   479
44113
0baa8bbd355a future_job: explicit indication of interrupts;
wenzelm
parents: 44111
diff changeset
   480
fun future_job group interrupts (e: unit -> 'a) =
44110
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   481
  let
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   482
    val result = Single_Assignment.var "future" : 'a result;
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   483
    val pos = Position.thread_data ();
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   484
    fun job ok =
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   485
      let
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   486
        val res =
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   487
          if ok then
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   488
            Exn.capture (fn () =>
44113
0baa8bbd355a future_job: explicit indication of interrupts;
wenzelm
parents: 44111
diff changeset
   489
              Multithreading.with_attributes
0baa8bbd355a future_job: explicit indication of interrupts;
wenzelm
parents: 44111
diff changeset
   490
                (if interrupts
0baa8bbd355a future_job: explicit indication of interrupts;
wenzelm
parents: 44111
diff changeset
   491
                 then Multithreading.private_interrupts else Multithreading.no_interrupts)
44295
e43f0ea90c9a more focused use of Multithreading.interrupted: retain interrupts within task group boundary, without loss of information;
wenzelm
parents: 44294
diff changeset
   492
                (fn _ => Position.setmp_thread_data pos e ())) ()
44110
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   493
          else Exn.interrupt_exn;
50914
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   494
      in assign_result group result (identify_result pos res) end;
44110
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   495
  in (result, job) end;
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   496
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   497
29366
1ffc8cbf39ec tuned map: reduced overhead due to bulk jobs;
wenzelm
parents: 29341
diff changeset
   498
(* fork *)
1ffc8cbf39ec tuned map: reduced overhead due to bulk jobs;
wenzelm
parents: 29341
diff changeset
   499
44427
c4a86d72a5cc tuned signature;
wenzelm
parents: 44387
diff changeset
   500
type params = {name: string, group: group option, deps: task list, pri: int, interrupts: bool};
c4a86d72a5cc tuned signature;
wenzelm
parents: 44387
diff changeset
   501
val default_params: params = {name = "", group = NONE, deps = [], pri = 0, interrupts = true};
44113
0baa8bbd355a future_job: explicit indication of interrupts;
wenzelm
parents: 44111
diff changeset
   502
44427
c4a86d72a5cc tuned signature;
wenzelm
parents: 44387
diff changeset
   503
fun forks ({name, group, deps, pri, interrupts}: params) es =
41674
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   504
  if null es then []
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   505
  else
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   506
    let
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   507
      val grp =
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   508
        (case group of
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   509
          NONE => worker_subgroup ()
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   510
        | SOME grp => grp);
41708
d2e6b1132df2 tuned signature;
wenzelm
parents: 41695
diff changeset
   511
      fun enqueue e queue =
41674
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   512
        let
44113
0baa8bbd355a future_job: explicit indication of interrupts;
wenzelm
parents: 44111
diff changeset
   513
          val (result, job) = future_job grp interrupts e;
41708
d2e6b1132df2 tuned signature;
wenzelm
parents: 41695
diff changeset
   514
          val (task, queue') = Task_Queue.enqueue name grp deps pri job queue;
41683
73dde8006820 maintain Task_Queue.group within Task_Queue.task;
wenzelm
parents: 41681
diff changeset
   515
          val future = Future {promised = false, task = task, result = result};
41708
d2e6b1132df2 tuned signature;
wenzelm
parents: 41695
diff changeset
   516
        in (future, queue') end;
41674
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   517
    in
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   518
      SYNCHRONIZED "enqueue" (fn () =>
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   519
        let
41708
d2e6b1132df2 tuned signature;
wenzelm
parents: 41695
diff changeset
   520
          val (futures, queue') = fold_map enqueue es (! queue);
d2e6b1132df2 tuned signature;
wenzelm
parents: 41695
diff changeset
   521
          val _ = queue := queue';
d2e6b1132df2 tuned signature;
wenzelm
parents: 41695
diff changeset
   522
          val minimal = forall (not o Task_Queue.known_task queue') deps;
41674
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   523
          val _ = if minimal then signal work_available else ();
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   524
          val _ = scheduler_check ();
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   525
        in futures end)
7da257539a8d tuned signature;
wenzelm
parents: 41673
diff changeset
   526
    end;
28162
55772e4e95e0 tuned check_cache;
wenzelm
parents: 28156
diff changeset
   527
50983
1290afb88f90 tuned signature;
wenzelm
parents: 50975
diff changeset
   528
fun fork e =
1290afb88f90 tuned signature;
wenzelm
parents: 50975
diff changeset
   529
  (singleton o forks) {name = "fork", group = NONE, deps = [], pri = 0, interrupts = true} e;
28186
6a8417f36837 cancel: check_scheduler;
wenzelm
parents: 28177
diff changeset
   530
6a8417f36837 cancel: check_scheduler;
wenzelm
parents: 28177
diff changeset
   531
29366
1ffc8cbf39ec tuned map: reduced overhead due to bulk jobs;
wenzelm
parents: 29341
diff changeset
   532
(* join *)
1ffc8cbf39ec tuned map: reduced overhead due to bulk jobs;
wenzelm
parents: 29341
diff changeset
   533
32099
5382c93108db propagate exceptions within future groups;
wenzelm
parents: 32096
diff changeset
   534
fun get_result x =
5382c93108db propagate exceptions within future groups;
wenzelm
parents: 32096
diff changeset
   535
  (case peek x of
37852
a902f158b4fc eliminated old-style sys_error/SYS_ERROR in favour of exception Fail -- after careful checking that there is no overlap with existing handling of that;
wenzelm
parents: 37690
diff changeset
   536
    NONE => Exn.Exn (Fail "Unfinished future")
39232
69c6d3e87660 more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents: 38236
diff changeset
   537
  | SOME res =>
69c6d3e87660 more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents: 38236
diff changeset
   538
      if Exn.is_interrupt_exn res then
44247
270366301bd7 more systematic handling of parallel exceptions;
wenzelm
parents: 44198
diff changeset
   539
        (case Task_Queue.group_status (Task_Queue.group_of_task (task_of x)) of
53190
5d92649a310e simplified Goal.forked_proofs: status is determined via group instead of dummy future (see also Pure/PIDE/execution.ML);
wenzelm
parents: 53189
diff changeset
   540
          [] => res
5d92649a310e simplified Goal.forked_proofs: status is determined via group instead of dummy future (see also Pure/PIDE/execution.ML);
wenzelm
parents: 53189
diff changeset
   541
        | exns => Exn.Exn (Par_Exn.make exns))
39232
69c6d3e87660 more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents: 38236
diff changeset
   542
      else res);
28186
6a8417f36837 cancel: check_scheduler;
wenzelm
parents: 28177
diff changeset
   543
49935
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   544
local
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   545
32095
ad4be204fdfe tuned tracing;
wenzelm
parents: 32058
diff changeset
   546
fun join_next deps = (*requires SYNCHRONIZED*)
41695
afdbec23b92b eliminated slightly odd abstract type Task_Queue.deps;
wenzelm
parents: 41683
diff changeset
   547
  if null deps then NONE
32224
a46f5e9b1718 dequeue_towards: always return active tasks;
wenzelm
parents: 32222
diff changeset
   548
  else
41681
b5d7b15166bf Future.join_results: discontinued post-hoc recording of dynamic dependencies;
wenzelm
parents: 41680
diff changeset
   549
    (case Unsynchronized.change_result queue (Task_Queue.dequeue_deps (Thread.self ()) deps) of
41695
afdbec23b92b eliminated slightly odd abstract type Task_Queue.deps;
wenzelm
parents: 41683
diff changeset
   550
      (NONE, []) => NONE
afdbec23b92b eliminated slightly odd abstract type Task_Queue.deps;
wenzelm
parents: 41683
diff changeset
   551
    | (NONE, deps') =>
afdbec23b92b eliminated slightly odd abstract type Task_Queue.deps;
wenzelm
parents: 41683
diff changeset
   552
        (worker_waiting deps' (fn () => worker_wait true work_finished); join_next deps')
32224
a46f5e9b1718 dequeue_towards: always return active tasks;
wenzelm
parents: 32222
diff changeset
   553
    | (SOME work, deps') => SOME (work, deps'));
32095
ad4be204fdfe tuned tracing;
wenzelm
parents: 32058
diff changeset
   554
32814
81897d30b97f added Task_Queue.depend (again) -- light-weight version for transitive graph;
wenzelm
parents: 32738
diff changeset
   555
fun execute_work NONE = ()
44110
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   556
  | execute_work (SOME (work, deps')) =
058520fa03a8 tuned source structure;
wenzelm
parents: 43952
diff changeset
   557
      (worker_joining (fn () => worker_exec work); join_work deps')
32814
81897d30b97f added Task_Queue.depend (again) -- light-weight version for transitive graph;
wenzelm
parents: 32738
diff changeset
   558
and join_work deps =
43538
de5c79682b56 more robust join_results: join_work needs to be uninterruptible, otherwise the task being dequeued by join_next might be never executed/finished!
wenzelm
parents: 42128
diff changeset
   559
  Multithreading.with_attributes Multithreading.no_interrupts
de5c79682b56 more robust join_results: join_work needs to be uninterruptible, otherwise the task being dequeued by join_next might be never executed/finished!
wenzelm
parents: 42128
diff changeset
   560
    (fn _ => execute_work (SYNCHRONIZED "join" (fn () => join_next deps)));
32814
81897d30b97f added Task_Queue.depend (again) -- light-weight version for transitive graph;
wenzelm
parents: 32738
diff changeset
   561
29551
95e469919c3e join_results: when dependencies are resulved (but not finished yet),
wenzelm
parents: 29431
diff changeset
   562
in
95e469919c3e join_results: when dependencies are resulved (but not finished yet),
wenzelm
parents: 29431
diff changeset
   563
29366
1ffc8cbf39ec tuned map: reduced overhead due to bulk jobs;
wenzelm
parents: 29341
diff changeset
   564
fun join_results xs =
41679
79716cb61bfd refined task timing: joining vs. waiting;
wenzelm
parents: 41674
diff changeset
   565
  let
79716cb61bfd refined task timing: joining vs. waiting;
wenzelm
parents: 41674
diff changeset
   566
    val _ =
79716cb61bfd refined task timing: joining vs. waiting;
wenzelm
parents: 41674
diff changeset
   567
      if forall is_finished xs then ()
79716cb61bfd refined task timing: joining vs. waiting;
wenzelm
parents: 41674
diff changeset
   568
      else if Multithreading.self_critical () then
52603
a44e9a1d5d8b tuned signature;
wenzelm
parents: 52558
diff changeset
   569
        raise Fail "Cannot join future values within critical section"
41695
afdbec23b92b eliminated slightly odd abstract type Task_Queue.deps;
wenzelm
parents: 41683
diff changeset
   570
      else if is_some (worker_task ()) then join_work (map task_of xs)
41681
b5d7b15166bf Future.join_results: discontinued post-hoc recording of dynamic dependencies;
wenzelm
parents: 41680
diff changeset
   571
      else List.app (ignore o Single_Assignment.await o result_of) xs;
41679
79716cb61bfd refined task timing: joining vs. waiting;
wenzelm
parents: 41674
diff changeset
   572
  in map get_result xs end;
28186
6a8417f36837 cancel: check_scheduler;
wenzelm
parents: 28177
diff changeset
   573
29551
95e469919c3e join_results: when dependencies are resulved (but not finished yet),
wenzelm
parents: 29431
diff changeset
   574
end;
95e469919c3e join_results: when dependencies are resulved (but not finished yet),
wenzelm
parents: 29431
diff changeset
   575
28647
8068cdc84e7e join_results: allow CRITICAL join of finished futures;
wenzelm
parents: 28645
diff changeset
   576
fun join_result x = singleton join_results x;
44330
b28e091f683a added Future.joins convenience;
wenzelm
parents: 44301
diff changeset
   577
fun joins xs = Par_Exn.release_all (join_results xs);
28647
8068cdc84e7e join_results: allow CRITICAL join of finished futures;
wenzelm
parents: 28645
diff changeset
   578
fun join x = Exn.release (join_result x);
28156
5205f7979b4f Functional threads as future values.
wenzelm
parents:
diff changeset
   579
54369
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   580
fun join_tasks tasks =
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   581
  if null tasks then ()
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   582
  else
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   583
    (singleton o forks)
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   584
      {name = "join_tasks", group = SOME (new_group NONE),
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   585
        deps = tasks, pri = 0, interrupts = false} I
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   586
    |> join;
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   587
29366
1ffc8cbf39ec tuned map: reduced overhead due to bulk jobs;
wenzelm
parents: 29341
diff changeset
   588
51325
bcd6b1aa4db5 more uniform Future.map: always internalize failure;
wenzelm
parents: 51283
diff changeset
   589
(* fast-path operations -- bypass task queue if possible *)
34277
7325a5e3587f added Future.promise/fulfill -- promised futures that are fulfilled by external means;
wenzelm
parents: 33416
diff changeset
   590
44294
a0ddd5760444 clarified Future.cond_forks: more uniform handling of exceptional situations;
wenzelm
parents: 44268
diff changeset
   591
fun value_result (res: 'a Exn.result) =
34277
7325a5e3587f added Future.promise/fulfill -- promised futures that are fulfilled by external means;
wenzelm
parents: 33416
diff changeset
   592
  let
45136
2afb928c71ca static dummy_task (again) to avoid a few extra allocations;
wenzelm
parents: 44427
diff changeset
   593
    val task = Task_Queue.dummy_task;
41683
73dde8006820 maintain Task_Queue.group within Task_Queue.task;
wenzelm
parents: 41681
diff changeset
   594
    val group = Task_Queue.group_of_task task;
35016
c0f2e49bccfc result: Single_Assignment.var;
wenzelm
parents: 34281
diff changeset
   595
    val result = Single_Assignment.var "value" : 'a result;
50914
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   596
    val _ = assign_result group result (identify_result (Position.thread_data ()) res);
41683
73dde8006820 maintain Task_Queue.group within Task_Queue.task;
wenzelm
parents: 41681
diff changeset
   597
  in Future {promised = false, task = task, result = result} end;
29366
1ffc8cbf39ec tuned map: reduced overhead due to bulk jobs;
wenzelm
parents: 29341
diff changeset
   598
44294
a0ddd5760444 clarified Future.cond_forks: more uniform handling of exceptional situations;
wenzelm
parents: 44268
diff changeset
   599
fun value x = value_result (Exn.Res x);
a0ddd5760444 clarified Future.cond_forks: more uniform handling of exceptional situations;
wenzelm
parents: 44268
diff changeset
   600
44330
b28e091f683a added Future.joins convenience;
wenzelm
parents: 44301
diff changeset
   601
fun cond_forks args es =
b28e091f683a added Future.joins convenience;
wenzelm
parents: 44301
diff changeset
   602
  if Multithreading.enabled () then forks args es
b28e091f683a added Future.joins convenience;
wenzelm
parents: 44301
diff changeset
   603
  else map (fn e => value_result (Exn.interruptible_capture e ())) es;
b28e091f683a added Future.joins convenience;
wenzelm
parents: 44301
diff changeset
   604
29384
a3c7e9ae9b71 more robust propagation of errors through bulk jobs;
wenzelm
parents: 29366
diff changeset
   605
fun map_future f x =
51325
bcd6b1aa4db5 more uniform Future.map: always internalize failure;
wenzelm
parents: 51283
diff changeset
   606
  if is_finished x then value_result (Exn.interruptible_capture (f o join) x)
49935
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   607
  else
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   608
    let
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   609
      val task = task_of x;
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   610
      val group = Task_Queue.group_of_task task;
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   611
      val (result, job) = future_job group true (fn () => f (join x));
29384
a3c7e9ae9b71 more robust propagation of errors through bulk jobs;
wenzelm
parents: 29366
diff changeset
   612
49935
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   613
      val extended = SYNCHRONIZED "extend" (fn () =>
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   614
        (case Task_Queue.extend task job (! queue) of
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   615
          SOME queue' => (queue := queue'; true)
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   616
        | NONE => false));
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   617
    in
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   618
      if extended then Future {promised = false, task = task, result = result}
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   619
      else
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   620
        (singleton o cond_forks)
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   621
          {name = "map_future", group = SOME group, deps = [task],
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   622
            pri = Task_Queue.pri_of_task task, interrupts = true}
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   623
          (fn () => f (join x))
d1ecb3554b25 clarified Future.map (again): finished value is mapped in-place, which saves task structures and changes error behaviour slightly (tolerance against canceled group of old value etc.);
wenzelm
parents: 49910
diff changeset
   624
    end;
28979
3ce619d8d432 fork/map: no inheritance of group (structure is nested, not parallel);
wenzelm
parents: 28972
diff changeset
   625
28191
9e5f556409c6 future: allow explicit group;
wenzelm
parents: 28186
diff changeset
   626
34277
7325a5e3587f added Future.promise/fulfill -- promised futures that are fulfilled by external means;
wenzelm
parents: 33416
diff changeset
   627
(* promised futures -- fulfilled by external means *)
7325a5e3587f added Future.promise/fulfill -- promised futures that are fulfilled by external means;
wenzelm
parents: 33416
diff changeset
   628
44298
b8f8488704e2 Future.promise: explicit abort operation (like uninterruptible future job);
wenzelm
parents: 44295
diff changeset
   629
fun promise_group group abort : 'a future =
34277
7325a5e3587f added Future.promise/fulfill -- promised futures that are fulfilled by external means;
wenzelm
parents: 33416
diff changeset
   630
  let
35016
c0f2e49bccfc result: Single_Assignment.var;
wenzelm
parents: 34281
diff changeset
   631
    val result = Single_Assignment.var "promise" : 'a result;
44298
b8f8488704e2 Future.promise: explicit abort operation (like uninterruptible future job);
wenzelm
parents: 44295
diff changeset
   632
    fun assign () = assign_result group result Exn.interrupt_exn
39243
307e3d07d19f Future.promise: more robust treatment of concurrent abort vs. fulfill (amending 047c96f41455);
wenzelm
parents: 39232
diff changeset
   633
      handle Fail _ => true
307e3d07d19f Future.promise: more robust treatment of concurrent abort vs. fulfill (amending 047c96f41455);
wenzelm
parents: 39232
diff changeset
   634
        | exn =>
44298
b8f8488704e2 Future.promise: explicit abort operation (like uninterruptible future job);
wenzelm
parents: 44295
diff changeset
   635
            if Exn.is_interrupt exn
b8f8488704e2 Future.promise: explicit abort operation (like uninterruptible future job);
wenzelm
parents: 44295
diff changeset
   636
            then raise Fail "Concurrent attempt to fulfill promise"
39243
307e3d07d19f Future.promise: more robust treatment of concurrent abort vs. fulfill (amending 047c96f41455);
wenzelm
parents: 39232
diff changeset
   637
            else reraise exn;
44298
b8f8488704e2 Future.promise: explicit abort operation (like uninterruptible future job);
wenzelm
parents: 44295
diff changeset
   638
    fun job () =
b8f8488704e2 Future.promise: explicit abort operation (like uninterruptible future job);
wenzelm
parents: 44295
diff changeset
   639
      Multithreading.with_attributes Multithreading.no_interrupts
47423
8a179a0493e3 more robust Future.fulfill wrt. duplicate assignment and interrupt;
wenzelm
parents: 47421
diff changeset
   640
        (fn _ => Exn.release (Exn.capture assign () before abort ()));
37854
047c96f41455 back to more strict dependencies, even for canceled groups (reverting parts of 02936e77a07c);
wenzelm
parents: 37852
diff changeset
   641
    val task = SYNCHRONIZED "enqueue_passive" (fn () =>
44298
b8f8488704e2 Future.promise: explicit abort operation (like uninterruptible future job);
wenzelm
parents: 44295
diff changeset
   642
      Unsynchronized.change_result queue (Task_Queue.enqueue_passive group job));
41683
73dde8006820 maintain Task_Queue.group within Task_Queue.task;
wenzelm
parents: 41681
diff changeset
   643
  in Future {promised = true, task = task, result = result} end;
34277
7325a5e3587f added Future.promise/fulfill -- promised futures that are fulfilled by external means;
wenzelm
parents: 33416
diff changeset
   644
44298
b8f8488704e2 Future.promise: explicit abort operation (like uninterruptible future job);
wenzelm
parents: 44295
diff changeset
   645
fun promise abort = promise_group (worker_subgroup ()) abort;
34277
7325a5e3587f added Future.promise/fulfill -- promised futures that are fulfilled by external means;
wenzelm
parents: 33416
diff changeset
   646
41683
73dde8006820 maintain Task_Queue.group within Task_Queue.task;
wenzelm
parents: 41681
diff changeset
   647
fun fulfill_result (Future {promised, task, result}) res =
39243
307e3d07d19f Future.promise: more robust treatment of concurrent abort vs. fulfill (amending 047c96f41455);
wenzelm
parents: 39232
diff changeset
   648
  if not promised then raise Fail "Not a promised future"
307e3d07d19f Future.promise: more robust treatment of concurrent abort vs. fulfill (amending 047c96f41455);
wenzelm
parents: 39232
diff changeset
   649
  else
307e3d07d19f Future.promise: more robust treatment of concurrent abort vs. fulfill (amending 047c96f41455);
wenzelm
parents: 39232
diff changeset
   650
    let
41683
73dde8006820 maintain Task_Queue.group within Task_Queue.task;
wenzelm
parents: 41681
diff changeset
   651
      val group = Task_Queue.group_of_task task;
50914
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   652
      val pos = Position.thread_data ();
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   653
      fun job ok =
fe4714886d92 identify future results more carefully, to avoid odd duplication of error messages, notably from forked goals;
wenzelm
parents: 50911
diff changeset
   654
        assign_result group result (if ok then identify_result pos res else Exn.interrupt_exn);
39243
307e3d07d19f Future.promise: more robust treatment of concurrent abort vs. fulfill (amending 047c96f41455);
wenzelm
parents: 39232
diff changeset
   655
      val _ =
307e3d07d19f Future.promise: more robust treatment of concurrent abort vs. fulfill (amending 047c96f41455);
wenzelm
parents: 39232
diff changeset
   656
        Multithreading.with_attributes Multithreading.no_interrupts (fn _ =>
307e3d07d19f Future.promise: more robust treatment of concurrent abort vs. fulfill (amending 047c96f41455);
wenzelm
parents: 39232
diff changeset
   657
          let
47423
8a179a0493e3 more robust Future.fulfill wrt. duplicate assignment and interrupt;
wenzelm
parents: 47421
diff changeset
   658
            val passive_job =
39243
307e3d07d19f Future.promise: more robust treatment of concurrent abort vs. fulfill (amending 047c96f41455);
wenzelm
parents: 39232
diff changeset
   659
              SYNCHRONIZED "fulfill_result" (fn () =>
307e3d07d19f Future.promise: more robust treatment of concurrent abort vs. fulfill (amending 047c96f41455);
wenzelm
parents: 39232
diff changeset
   660
                Unsynchronized.change_result queue
307e3d07d19f Future.promise: more robust treatment of concurrent abort vs. fulfill (amending 047c96f41455);
wenzelm
parents: 39232
diff changeset
   661
                  (Task_Queue.dequeue_passive (Thread.self ()) task));
47423
8a179a0493e3 more robust Future.fulfill wrt. duplicate assignment and interrupt;
wenzelm
parents: 47421
diff changeset
   662
          in
8a179a0493e3 more robust Future.fulfill wrt. duplicate assignment and interrupt;
wenzelm
parents: 47421
diff changeset
   663
            (case passive_job of
8a179a0493e3 more robust Future.fulfill wrt. duplicate assignment and interrupt;
wenzelm
parents: 47421
diff changeset
   664
              SOME true => worker_exec (task, [job])
8a179a0493e3 more robust Future.fulfill wrt. duplicate assignment and interrupt;
wenzelm
parents: 47421
diff changeset
   665
            | SOME false => ()
8a179a0493e3 more robust Future.fulfill wrt. duplicate assignment and interrupt;
wenzelm
parents: 47421
diff changeset
   666
            | NONE => ignore (job (not (Task_Queue.is_canceled group))))
8a179a0493e3 more robust Future.fulfill wrt. duplicate assignment and interrupt;
wenzelm
parents: 47421
diff changeset
   667
          end);
41681
b5d7b15166bf Future.join_results: discontinued post-hoc recording of dynamic dependencies;
wenzelm
parents: 41680
diff changeset
   668
      val _ =
41695
afdbec23b92b eliminated slightly odd abstract type Task_Queue.deps;
wenzelm
parents: 41683
diff changeset
   669
        if is_some (Single_Assignment.peek result) then ()
afdbec23b92b eliminated slightly odd abstract type Task_Queue.deps;
wenzelm
parents: 41683
diff changeset
   670
        else worker_waiting [task] (fn () => ignore (Single_Assignment.await result));
39243
307e3d07d19f Future.promise: more robust treatment of concurrent abort vs. fulfill (amending 047c96f41455);
wenzelm
parents: 39232
diff changeset
   671
    in () end;
34277
7325a5e3587f added Future.promise/fulfill -- promised futures that are fulfilled by external means;
wenzelm
parents: 33416
diff changeset
   672
43761
e72ba84ae58f tuned signature -- corresponding to Scala version;
wenzelm
parents: 43665
diff changeset
   673
fun fulfill x res = fulfill_result x (Exn.Res res);
34277
7325a5e3587f added Future.promise/fulfill -- promised futures that are fulfilled by external means;
wenzelm
parents: 33416
diff changeset
   674
7325a5e3587f added Future.promise/fulfill -- promised futures that are fulfilled by external means;
wenzelm
parents: 33416
diff changeset
   675
54369
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   676
(* group snapshot *)
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   677
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   678
fun group_snapshot group =
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   679
  SYNCHRONIZED "group_snapshot" (fn () =>
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   680
    Task_Queue.group_tasks (! queue) group);
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   681
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   682
49906
06a3570b0f0a more official Future.terminate;
wenzelm
parents: 49894
diff changeset
   683
(* terminate *)
06a3570b0f0a more official Future.terminate;
wenzelm
parents: 49894
diff changeset
   684
06a3570b0f0a more official Future.terminate;
wenzelm
parents: 49894
diff changeset
   685
fun terminate group =
54369
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   686
  SYNCHRONIZED "terminate" (fn () =>
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   687
    let val _ = cancel_group_unsynchronized group;
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   688
    in Task_Queue.group_tasks (! queue) group end)
7bf7b2903fb9 tuned signature;
wenzelm
parents: 53190
diff changeset
   689
  |> join_tasks;
49906
06a3570b0f0a more official Future.terminate;
wenzelm
parents: 49894
diff changeset
   690
06a3570b0f0a more official Future.terminate;
wenzelm
parents: 49894
diff changeset
   691
32228
7622c03141b0 scheduler: shutdown spontaneously (after some delay) if queue is empty;
wenzelm
parents: 32227
diff changeset
   692
(* shutdown *)
29366
1ffc8cbf39ec tuned map: reduced overhead due to bulk jobs;
wenzelm
parents: 29341
diff changeset
   693
28203
88f18387f1c9 shutdown: global join-and-shutdown operation;
wenzelm
parents: 28202
diff changeset
   694
fun shutdown () =
51283
fefd07697979 disallow shutdown from worker, which would lead to deadlock since the scheduler cannot terminate;
wenzelm
parents: 51281
diff changeset
   695
  if not Multithreading.available then ()
fefd07697979 disallow shutdown from worker, which would lead to deadlock since the scheduler cannot terminate;
wenzelm
parents: 51281
diff changeset
   696
  else if is_some (worker_task ()) then
fefd07697979 disallow shutdown from worker, which would lead to deadlock since the scheduler cannot terminate;
wenzelm
parents: 51281
diff changeset
   697
    raise Fail "Cannot shutdown while running as worker thread"
fefd07697979 disallow shutdown from worker, which would lead to deadlock since the scheduler cannot terminate;
wenzelm
parents: 51281
diff changeset
   698
  else
28276
fbc707811203 shutdown only if Multithreading.available;
wenzelm
parents: 28242
diff changeset
   699
    SYNCHRONIZED "shutdown" (fn () =>
51279
f4a2fa9286e9 tuned messages;
wenzelm
parents: 51046
diff changeset
   700
      while scheduler_active () do
f4a2fa9286e9 tuned messages;
wenzelm
parents: 51046
diff changeset
   701
       (Multithreading.tracing 1 (fn () => "SHUTDOWN: wait");
51283
fefd07697979 disallow shutdown from worker, which would lead to deadlock since the scheduler cannot terminate;
wenzelm
parents: 51281
diff changeset
   702
        wait scheduler_event));
28203
88f18387f1c9 shutdown: global join-and-shutdown operation;
wenzelm
parents: 28202
diff changeset
   703
29366
1ffc8cbf39ec tuned map: reduced overhead due to bulk jobs;
wenzelm
parents: 29341
diff changeset
   704
1ffc8cbf39ec tuned map: reduced overhead due to bulk jobs;
wenzelm
parents: 29341
diff changeset
   705
(*final declarations of this structure!*)
1ffc8cbf39ec tuned map: reduced overhead due to bulk jobs;
wenzelm
parents: 29341
diff changeset
   706
val map = map_future;
1ffc8cbf39ec tuned map: reduced overhead due to bulk jobs;
wenzelm
parents: 29341
diff changeset
   707
28156
5205f7979b4f Functional threads as future values.
wenzelm
parents:
diff changeset
   708
end;
28972
cb8a2c3e188f renamed type Future.T to future;
wenzelm
parents: 28647
diff changeset
   709
cb8a2c3e188f renamed type Future.T to future;
wenzelm
parents: 28647
diff changeset
   710
type 'a future = 'a Future.future;
cb8a2c3e188f renamed type Future.T to future;
wenzelm
parents: 28647
diff changeset
   711