--- a/src/Pure/Concurrent/future.ML Mon Sep 08 16:08:18 2008 +0200
+++ b/src/Pure/Concurrent/future.ML Mon Sep 08 16:08:23 2008 +0200
@@ -7,13 +7,16 @@
signature FUTURE =
sig
+ type task = TaskQueue.task
+ type group = TaskQueue.group
type 'a T
- eqtype id
- val id_of: 'a T -> id
- val interrupt: id -> unit
- val dependent_future: id list -> (unit -> 'a) -> 'a T
- val future: (unit -> 'a) -> 'a T
- val await: 'a T -> 'a
+ val task_of: 'a T -> task
+ val group_of: 'a T -> group option
+ val future: group option -> task list -> (unit -> 'a) -> 'a T
+ val fork: (unit -> 'a) -> 'a T
+ val join: 'a T -> 'a
+ val interrupt: task -> unit
+ val interrupt_group: group -> unit
end;
structure Future: FUTURE =
@@ -33,111 +36,71 @@
val _ = Mutex.unlock lock;
in Exn.release result end) ();
-fun wait () = ConditionVar.wait (cond, lock);
-fun wait_timeout timeout = ConditionVar.waitUntil (cond, lock, Time.+ (Time.now (), timeout));
+fun wait () = (*requires SYNCHRONIZED*)
+ ConditionVar.wait (cond, lock);
-fun notify_all () = ConditionVar.broadcast cond;
+fun wait_timeout timeout = (*requires SYNCHRONIZED*)
+ ConditionVar.waitUntil (cond, lock, Time.+ (Time.now (), timeout));
+
+fun notify_all () = (*requires SYNCHRONIZED*)
+ ConditionVar.broadcast cond;
end;
-(* typed futures, unytped ids *)
-
-datatype 'a T = Future of serial * 'a Exn.result option ref;
-
-datatype id = Id of serial;
-fun id_of (Future (id, _)) = Id id;
+(* datatype future *)
-local val tag = Universal.tag () : serial Universal.tag in
- fun get_id () = Thread.getLocal tag;
- fun put_id id = Thread.setLocal (tag, id);
-end;
-
-
-(* ordered queue of tasks *)
-
-datatype task =
- Task of (unit -> unit) |
- Running of Thread.thread;
-
-datatype queue = Queue of task IntGraph.T * (serial * (unit -> unit)) Queue.T;
-
-val empty_queue = Queue (IntGraph.empty, Queue.empty);
+type task = TaskQueue.task;
+type group = TaskQueue.group;
-fun check_cache (queue as Queue (tasks, cache)) =
- if not (Queue.is_empty cache) then queue
- else
- let fun ready (id, (Task task, ([], _))) = Queue.enqueue (id, task) | ready _ = I
- in Queue (tasks, IntGraph.fold ready tasks Queue.empty) end;
-
-val next_task = check_cache #> (fn queue as Queue (tasks, cache) =>
- if Queue.is_empty cache then (NONE, queue)
- else
- let val (task, cache') = Queue.dequeue cache
- in (SOME task, Queue (tasks, cache')) end);
+datatype 'a T = Future of
+ {task: task,
+ group: group option,
+ result: 'a Exn.result option ref};
-fun get_task (Queue (tasks, _)) id = IntGraph.get_node tasks id;
-
-fun new_task deps id task (Queue (tasks, _)) =
- let
- fun add_dep (Id dep) G = IntGraph.add_edge_acyclic (dep, id) G
- handle IntGraph.UNDEF _ => G; (*dep already finished*)
- val tasks' = tasks |> IntGraph.new_node (id, Task task) |> fold add_dep deps;
- in Queue (tasks', Queue.empty) end;
-
-fun running_task id thread (Queue (tasks, cache)) =
- Queue (IntGraph.map_node id (K (Running thread)) tasks, cache);
-
-fun finished_task id (Queue (tasks, _)) =
- Queue (IntGraph.del_nodes [id] tasks, Queue.empty);
+fun task_of (Future {task, ...}) = task;
+fun group_of (Future {group, ...}) = group;
(* global state *)
-val tasks = ref empty_queue;
+val queue = ref TaskQueue.empty;
val scheduler = ref (NONE: Thread.thread option);
val workers = ref ([]: Thread.thread list);
-fun interrupt (Id id) = SYNCHRONIZED (fn () =>
- (case try (get_task (! tasks)) id of
- SOME (Running thread) => Thread.interrupt thread
- | _ => ()));
-
-
(* worker thread *)
local val active = ref 0 in
fun change_active b = (*requires SYNCHRONIZED*)
- let
- val _ = change active (fn n => if b then n + 1 else n - 1);
- val n = ! active;
- val _ = Multithreading.tracing 1 (fn () => "SCHEDULE: " ^ string_of_int n ^ " active");
- in () end;
+ (change active (fn n => if b then n + 1 else n - 1);
+ Multithreading.tracing 1 (fn () => "SCHEDULE: " ^ string_of_int (! active) ^ " active"));
end;
fun excessive_threads () = false; (* FIXME *)
-fun worker_stop () = SYNCHRONIZED (fn () =>
- (change_active false; change workers (filter (fn t => not (Thread.equal (t, Thread.self ()))))));
-
-fun worker_wait () = SYNCHRONIZED (fn () =>
- (change_active false; wait (); change_active true));
+fun worker_next () = (*requires SYNCHRONIZED*)
+ if excessive_threads () then
+ (change_active false;
+ change workers (filter_out (fn thread => Thread.equal (thread, Thread.self ())));
+ NONE)
+ else
+ (case change_result queue (TaskQueue.dequeue (Thread.self ())) of
+ NONE => (change_active false; wait (); change_active true; worker_next ())
+ | some => some);
fun worker_loop () =
- if excessive_threads () then worker_stop ()
- else
- (case SYNCHRONIZED (fn () => change_result tasks next_task) of
- NONE => (worker_wait (); worker_loop ())
- | SOME (id, task) =>
- let
- val _ = SYNCHRONIZED (fn () => change tasks (running_task id (Thread.self ())));
- val _ = task ();
- val _ = SYNCHRONIZED (fn () => change tasks (finished_task id));
- val _ = notify_all ();
- in worker_loop () end);
+ (case SYNCHRONIZED worker_next of
+ NONE => ()
+ | SOME (task, run) =>
+ let
+ val _ = TaskQueue.set_thread_data (SOME task);
+ val _ = run ();
+ val _ = TaskQueue.set_thread_data NONE;
+ val _ = SYNCHRONIZED (fn () => (change queue (TaskQueue.finished task); notify_all ()));
+ in worker_loop () end);
fun worker_start () = SYNCHRONIZED (fn () =>
(change_active true;
@@ -151,7 +114,7 @@
val m = Multithreading.max_threads_value ();
val k = m - length (! workers);
val _ = if k > 0 then funpow k worker_start () else ();
- in wait_timeout (Time.fromSeconds 1); scheduler_loop () end;
+ in wait_timeout (Time.fromMilliseconds 300); scheduler_loop () end;
fun check_scheduler () = SYNCHRONIZED (fn () =>
let
@@ -168,30 +131,32 @@
(* future values *)
-fun dependent_future deps (e: unit -> 'a) =
+fun future group deps (e: unit -> 'a) =
let
val _ = check_scheduler ();
- val r = ref (NONE: 'a Exn.result option);
- val task = Multithreading.with_attributes (Thread.getAttributes ())
- (fn _ => fn () => r := SOME (Exn.capture e ()));
+ val result = ref (NONE: 'a Exn.result option);
+ val run = Multithreading.with_attributes (Thread.getAttributes ())
+ (fn _ => fn () => result := SOME (Exn.capture e ()));
+ val task = SYNCHRONIZED (fn () =>
+ change_result queue (TaskQueue.enqueue group deps run) before notify_all ());
+ in Future {task = task, group = group, result = result} end;
- val id = serial ();
- val _ = SYNCHRONIZED (fn () => change tasks (new_task deps id task));
- val _ = notify_all ();
+fun fork e = future NONE [] e;
- in Future (id, r) end;
-
-fun future e = dependent_future [] e;
-
-fun await (Future (_, r)) =
+fun join (Future {result, ...}) =
let
val _ = check_scheduler ();
+ fun loop () =
+ (case ! result of
+ NONE => (wait (); loop ())
+ | SOME res => res);
+ in Exn.release (SYNCHRONIZED loop) end;
- fun loop () =
- (case SYNCHRONIZED (fn () => ! r) of
- NONE => (SYNCHRONIZED (fn () => wait ()); loop ())
- | SOME res => Exn.release res);
- in loop () end;
+
+(* interrupts *)
+
+fun interrupt task = SYNCHRONIZED (fn () => TaskQueue.interrupt (! queue) task);
+fun interrupt_group group = SYNCHRONIZED (fn () => TaskQueue.interrupt_group (! queue) group);
end;