(* Title: Pure/Concurrent/task_queue.ML
Author: Makarius
Ordered queue of grouped tasks.
*)
signature TASK_QUEUE =
sig
type task
val dummy_task: task
val name_of_task: task -> string
val pri_of_task: task -> int
val str_of_task: task -> string
val timing_of_task: task -> Time.time * Time.time * string list
type group
val new_group: group option -> group
val group_id: group -> int
val eq_group: group * group -> bool
val cancel_group: group -> exn -> unit
val is_canceled: group -> bool
val group_status: group -> exn list
val str_of_group: group -> string
type queue
val empty: queue
val all_passive: queue -> bool
val status: queue -> {ready: int, pending: int, running: int, passive: int}
val cancel: queue -> group -> bool
val cancel_all: queue -> group list
val finish: task -> queue -> bool * queue
val enqueue_passive: group -> (unit -> bool) -> queue -> task * queue
val enqueue: string -> group -> task list -> int -> (bool -> bool) ->
queue -> (task * bool) * queue
val extend: task -> (bool -> bool) -> queue -> queue option
val dequeue_passive: Thread.thread -> task -> queue -> bool * queue
val dequeue: Thread.thread -> queue -> (task * group * (bool -> bool) list) option * queue
type deps
val init_deps: task list -> deps
val finished_deps: deps -> bool
val dequeue_deps: Thread.thread -> deps -> queue ->
(((task * group * (bool -> bool) list) option * deps) * queue)
val running: task -> (unit -> 'a) -> 'a
val joining: task -> (unit -> 'a) -> 'a
val waiting: task -> deps -> (unit -> 'a) -> 'a
end;
structure Task_Queue: TASK_QUEUE =
struct
val new_id = Synchronized.counter ();
(** grouped tasks **)
(* tasks *)
type timing = Time.time * Time.time * string list; (*run, wait, wait dependencies*)
fun new_timing () =
Synchronized.var "timing" ((Time.zeroTime, Time.zeroTime, []): timing);
abstype task = Task of
{name: string,
id: int,
pri: int option,
timing: timing Synchronized.var}
with
val dummy_task = Task {name = "", id = ~1, pri = NONE, timing = new_timing ()};
fun new_task name pri = Task {name = name, id = new_id (), pri = pri, timing = new_timing ()};
fun name_of_task (Task {name, ...}) = name;
fun pri_of_task (Task {pri, ...}) = the_default 0 pri;
fun str_of_task (Task {name, id, ...}) =
if name = "" then string_of_int id else string_of_int id ^ " (" ^ name ^ ")";
fun timing_of_task (Task {timing, ...}) = Synchronized.value timing;
fun update_timing update (Task {timing, ...}) e =
let
val start = Time.now ();
val result = Exn.capture e ();
val t = Time.- (Time.now (), start);
val _ = Synchronized.change timing (update t);
in Exn.release result end;
fun task_ord (Task {id = id1, pri = pri1, ...}, Task {id = id2, pri = pri2, ...}) =
prod_ord (rev_order o option_ord int_ord) int_ord ((pri1, id1), (pri2, id2));
val eq_task = is_equal o task_ord;
end;
structure Task_Graph = Graph(type key = task val ord = task_ord);
(* nested groups *)
abstype group = Group of
{parent: group option,
id: int,
status: exn list Synchronized.var}
with
fun make_group (parent, id, status) = Group {parent = parent, id = id, status = status};
fun new_group parent = make_group (parent, new_id (), Synchronized.var "group" []);
fun group_id (Group {id, ...}) = id;
fun eq_group (group1, group2) = group_id group1 = group_id group2;
fun group_ancestry (Group {parent, id, ...}) =
id :: (case parent of NONE => [] | SOME group => group_ancestry group);
(* group status *)
fun cancel_group (Group {status, ...}) exn =
Synchronized.change status
(fn exns =>
if not (Exn.is_interrupt exn) orelse null exns then exn :: exns
else exns);
fun is_canceled (Group {parent, status, ...}) =
not (null (Synchronized.value status)) orelse
(case parent of NONE => false | SOME group => is_canceled group);
fun group_status (Group {parent, status, ...}) =
Synchronized.value status @
(case parent of NONE => [] | SOME group => group_status group);
fun str_of_group group =
(is_canceled group ? enclose "(" ")") (string_of_int (group_id group));
end;
(** queue of jobs and groups **)
(* jobs *)
datatype job =
Job of (bool -> bool) list |
Running of Thread.thread |
Passive of unit -> bool;
type jobs = (group * job) Task_Graph.T;
fun get_group (jobs: jobs) task = #1 (Task_Graph.get_node jobs task);
fun get_job (jobs: jobs) task = #2 (Task_Graph.get_node jobs task);
fun set_job task job (jobs: jobs) = Task_Graph.map_node task (fn (group, _) => (group, job)) jobs;
fun add_job task dep (jobs: jobs) =
Task_Graph.add_edge (dep, task) jobs handle Task_Graph.UNDEF _ => jobs;
fun get_deps (jobs: jobs) task =
Task_Graph.imm_preds jobs task handle Task_Graph.UNDEF _ => [];
(* queue *)
datatype queue = Queue of
{groups: task list Inttab.table, (*groups with presently known members*)
jobs: jobs}; (*job dependency graph*)
fun make_queue groups jobs = Queue {groups = groups, jobs = jobs};
val empty = make_queue Inttab.empty Task_Graph.empty;
(* job status *)
fun ready_job task ((group, Job list), ([], _)) = SOME (task, group, rev list)
| ready_job task ((group, Passive abort), ([], _)) =
if is_canceled group then SOME (task, group, [fn _ => abort ()])
else NONE
| ready_job _ _ = NONE;
fun active_job (_, Job _) = SOME ()
| active_job (_, Running _) = SOME ()
| active_job (group, Passive _) = if is_canceled group then SOME () else NONE;
fun all_passive (Queue {jobs, ...}) =
is_none (Task_Graph.get_first (active_job o #1 o #2) jobs);
(* queue status *)
fun status (Queue {jobs, ...}) =
let
val (x, y, z, w) =
Task_Graph.fold (fn (_, ((_, job), (deps, _))) => fn (x, y, z, w) =>
(case job of
Job _ => if null deps then (x + 1, y, z, w) else (x, y + 1, z, w)
| Running _ => (x, y, z + 1, w)
| Passive _ => (x, y, z, w + 1)))
jobs (0, 0, 0, 0);
in {ready = x, pending = y, running = z, passive = w} end;
(** task queue operations **)
(* cancel -- peers and sub-groups *)
fun cancel (Queue {groups, jobs}) group =
let
val _ = cancel_group group Exn.Interrupt;
val tasks = Inttab.lookup_list groups (group_id group);
val running =
fold (get_job jobs #> (fn Running t => insert Thread.equal t | _ => I)) tasks [];
val _ = List.app Simple_Thread.interrupt running;
in null running end;
fun cancel_all (Queue {jobs, ...}) =
let
fun cancel_job (group, job) (groups, running) =
(cancel_group group Exn.Interrupt;
(case job of
Running t => (insert eq_group group groups, insert Thread.equal t running)
| _ => (groups, running)));
val (running_groups, running) = Task_Graph.fold (cancel_job o #1 o #2) jobs ([], []);
val _ = List.app Simple_Thread.interrupt running;
in running_groups end;
(* finish *)
fun finish task (Queue {groups, jobs}) =
let
val group = get_group jobs task;
val groups' = groups
|> fold (fn gid => Inttab.remove_list eq_task (gid, task)) (group_ancestry group);
val jobs' = Task_Graph.del_node task jobs;
val maximal = null (Task_Graph.imm_succs jobs task);
in (maximal, make_queue groups' jobs') end;
(* enqueue *)
fun enqueue_passive group abort (Queue {groups, jobs}) =
let
val task = new_task "passive" NONE;
val groups' = groups
|> fold (fn gid => Inttab.cons_list (gid, task)) (group_ancestry group);
val jobs' = jobs |> Task_Graph.new_node (task, (group, Passive abort));
in (task, make_queue groups' jobs') end;
fun enqueue name group deps pri job (Queue {groups, jobs}) =
let
val task = new_task name (SOME pri);
val groups' = groups
|> fold (fn gid => Inttab.cons_list (gid, task)) (group_ancestry group);
val jobs' = jobs
|> Task_Graph.new_node (task, (group, Job [job]))
|> fold (add_job task) deps
|> fold (fold (add_job task) o get_deps jobs) deps;
val minimal = null (get_deps jobs' task);
in ((task, minimal), make_queue groups' jobs') end;
fun extend task job (Queue {groups, jobs}) =
(case try (get_job jobs) task of
SOME (Job list) => SOME (make_queue groups (set_job task (Job (job :: list)) jobs))
| _ => NONE);
(* dequeue *)
fun dequeue_passive thread task (queue as Queue {groups, jobs}) =
(case try (get_job jobs) task of
SOME (Passive _) =>
let val jobs' = set_job task (Running thread) jobs
in (true, make_queue groups jobs') end
| _ => (false, queue));
fun dequeue thread (queue as Queue {groups, jobs}) =
(case Task_Graph.get_first (uncurry ready_job) jobs of
SOME (result as (task, _, _)) =>
let val jobs' = set_job task (Running thread) jobs
in (SOME result, make_queue groups jobs') end
| NONE => (NONE, queue));
(* dequeue wrt. dynamic dependencies *)
abstype deps = Deps of task list
with
fun init_deps tasks = Deps tasks;
fun finished_deps (Deps tasks) = null tasks;
fun insert_deps (Deps tasks) = fold (insert (op =) o name_of_task) tasks;
fun dequeue_deps thread (Deps deps) (queue as Queue {groups, jobs}) =
let
fun ready task = ready_job task (Task_Graph.get_entry jobs task);
val tasks = filter (can (Task_Graph.get_node jobs)) deps;
fun result (res as (task, _, _)) =
let val jobs' = set_job task (Running thread) jobs
in ((SOME res, Deps tasks), make_queue groups jobs') end;
in
(case get_first ready tasks of
SOME res => result res
| NONE =>
(case get_first (get_first ready o get_deps jobs) tasks of
SOME res => result res
| NONE => ((NONE, Deps tasks), queue)))
end;
end;
(* timing *)
fun running task =
update_timing (fn t => fn (a, b, ds) => (Time.+ (a, t), b, ds)) task;
fun joining task =
update_timing (fn t => fn (a, b, ds) => (Time.- (a, t), b, ds)) task;
fun waiting task deps =
update_timing (fn t => fn (a, b, ds) => (Time.- (a, t), Time.+ (b, t), insert_deps deps ds)) task;
end;