wenzelm@28156
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(* Title: Pure/Concurrent/future.ML
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wenzelm@28156
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Author: Makarius
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wenzelm@28156
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wenzelm@32250
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Future values, see also
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wenzelm@32250
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http://www4.in.tum.de/~wenzelm/papers/parallel-isabelle.pdf
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wenzelm@38175
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http://www4.in.tum.de/~wenzelm/papers/parallel-ml.pdf
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wenzelm@28201
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wenzelm@28201
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Notes:
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wenzelm@28201
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wenzelm@28201
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* Futures are similar to delayed evaluation, i.e. delay/force is
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wenzelm@28201
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generalized to fork/join (and variants). The idea is to model
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wenzelm@28201
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parallel value-oriented computations, but *not* communicating
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wenzelm@28201
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processes.
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wenzelm@28201
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wenzelm@28201
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* Futures are grouped; failure of one group member causes the whole
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wenzelm@32220
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group to be interrupted eventually. Groups are block-structured.
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wenzelm@28201
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wenzelm@28201
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* Forked futures are evaluated spontaneously by a farm of worker
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wenzelm@28201
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threads in the background; join resynchronizes the computation and
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wenzelm@28201
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delivers results (values or exceptions).
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wenzelm@28201
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wenzelm@28201
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* The pool of worker threads is limited, usually in correlation with
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wenzelm@28201
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the number of physical cores on the machine. Note that allocation
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wenzelm@28201
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of runtime resources is distorted either if workers yield CPU time
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wenzelm@28201
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(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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wenzelm@34277
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wenzelm@34277
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* Promised futures are fulfilled by external means. There is no
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wenzelm@34277
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associated evaluation task, but other futures can depend on them
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wenzelm@34277
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as usual.
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wenzelm@28156
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*)
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signature FUTURE =
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wenzelm@28156
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sig
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wenzelm@32823
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val worker_task: unit -> Task_Queue.task option
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wenzelm@32122
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val worker_group: unit -> Task_Queue.group option
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wenzelm@38133
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val worker_subgroup: unit -> Task_Queue.group
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wenzelm@28972
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type 'a future
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val task_of: 'a future -> Task_Queue.task
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val peek: 'a future -> 'a Exn.result option
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wenzelm@28972
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val is_finished: 'a future -> bool
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wenzelm@44993
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val cancel_group: Task_Queue.group -> unit
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wenzelm@44993
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val cancel: 'a future -> unit
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wenzelm@44996
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type fork_params =
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wenzelm@44996
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{name: string, group: Task_Queue.group option, deps: Task_Queue.task list,
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pri: int, interrupts: bool}
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val forks: fork_params -> (unit -> 'a) list -> 'a future list
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wenzelm@29120
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val fork_pri: int -> (unit -> 'a) -> 'a future
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wenzelm@32729
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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 join: 'a future -> 'a
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val value: 'a -> 'a future
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val map: ('a -> 'b) -> 'a future -> 'b future
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val cond_forks: fork_params -> (unit -> 'a) list -> 'a future list
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val promise_group: Task_Queue.group -> 'a future
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val promise: 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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wenzelm@30621
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val interruptible_task: ('a -> 'b) -> 'a -> 'b
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wenzelm@28203
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val shutdown: unit -> unit
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wenzelm@38492
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val status: (unit -> 'a) -> 'a
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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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(* identifiers *)
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local
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val tag = Universal.tag () : Task_Queue.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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wenzelm@42563
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val worker_group = Option.map Task_Queue.group_of_task o worker_task;
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wenzelm@38133
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fun worker_subgroup () = Task_Queue.new_group (worker_group ());
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wenzelm@34277
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wenzelm@42559
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fun worker_joining e =
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wenzelm@42559
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(case worker_task () of
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wenzelm@42559
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NONE => e ()
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| SOME task => Task_Queue.joining task e);
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wenzelm@42559
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wenzelm@42560
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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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wenzelm@42560
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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_Queue.task,
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result: 'a result};
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fun task_of (Future {task, ...}) = task;
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wenzelm@32257
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fun result_of (Future {result, ...}) = result;
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wenzelm@35016
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fun peek x = Single_Assignment.peek (result_of x);
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wenzelm@28558
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fun is_finished x = is_some (peek x);
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wenzelm@28320
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wenzelm@28167
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wenzelm@28177
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wenzelm@28177
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(** scheduling **)
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wenzelm@28177
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wenzelm@28177
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(* synchronization *)
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wenzelm@28156
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wenzelm@32219
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val scheduler_event = ConditionVar.conditionVar ();
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wenzelm@32219
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val work_available = ConditionVar.conditionVar ();
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wenzelm@32219
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val work_finished = ConditionVar.conditionVar ();
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wenzelm@32219
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local
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val lock = Mutex.mutex ();
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in
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wenzelm@37216
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fun SYNCHRONIZED name = Simple_Thread.synchronized name lock;
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wenzelm@32219
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fun wait cond = (*requires SYNCHRONIZED*)
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wenzelm@32298
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Multithreading.sync_wait NONE NONE cond lock;
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wenzelm@28206
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wenzelm@32298
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fun wait_timeout timeout cond = (*requires SYNCHRONIZED*)
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wenzelm@32298
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Multithreading.sync_wait NONE (SOME (Time.+ (Time.now (), timeout))) cond lock;
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wenzelm@28166
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wenzelm@32219
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fun signal cond = (*requires SYNCHRONIZED*)
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wenzelm@32219
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ConditionVar.signal cond;
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wenzelm@32219
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wenzelm@32219
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fun broadcast cond = (*requires SYNCHRONIZED*)
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ConditionVar.broadcast cond;
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wenzelm@32252
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fun broadcast_work () = (*requires SYNCHRONIZED*)
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wenzelm@32252
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(ConditionVar.broadcast work_available;
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wenzelm@32225
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ConditionVar.broadcast work_finished);
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wenzelm@32225
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wenzelm@28156
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end;
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wenzelm@28156
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wenzelm@33431
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(* global state *)
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wenzelm@33431
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wenzelm@33431
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val queue = Unsynchronized.ref Task_Queue.empty;
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wenzelm@33431
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val next = Unsynchronized.ref 0;
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wenzelm@33431
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val scheduler = Unsynchronized.ref (NONE: Thread.thread option);
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wenzelm@33431
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val canceled = Unsynchronized.ref ([]: Task_Queue.group list);
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wenzelm@33431
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val do_shutdown = Unsynchronized.ref false;
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wenzelm@33431
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val max_workers = Unsynchronized.ref 0;
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wenzelm@33431
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val max_active = Unsynchronized.ref 0;
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wenzelm@33432
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val worker_trend = Unsynchronized.ref 0;
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wenzelm@33431
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wenzelm@33431
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datatype worker_state = Working | Waiting | Sleeping;
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wenzelm@33431
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val workers = Unsynchronized.ref ([]: (Thread.thread * worker_state Unsynchronized.ref) list);
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wenzelm@33431
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wenzelm@33431
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fun count_workers state = (*requires SYNCHRONIZED*)
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wenzelm@33431
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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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wenzelm@33431
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wenzelm@33431
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wenzelm@44993
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(* cancellation primitives *)
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wenzelm@32119
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wenzelm@44993
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fun interruptible_task f x =
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wenzelm@44993
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if Multithreading.available then
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wenzelm@44993
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Multithreading.with_attributes
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wenzelm@44993
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(if is_some (worker_task ())
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wenzelm@44993
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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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wenzelm@28156
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wenzelm@34279
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fun cancel_now group = (*requires SYNCHRONIZED*)
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wenzelm@34280
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Task_Queue.cancel (! queue) group;
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wenzelm@34279
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wenzelm@34279
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fun cancel_later group = (*requires SYNCHRONIZED*)
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wenzelm@32738
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(Unsynchronized.change canceled (insert Task_Queue.eq_group group);
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wenzelm@32738
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broadcast scheduler_event);
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wenzelm@29341
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wenzelm@44993
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wenzelm@44993
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(* worker threads *)
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wenzelm@44993
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wenzelm@44993
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fun worker_exec (task, jobs) =
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wenzelm@28167
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let
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wenzelm@42563
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val group = Task_Queue.group_of_task task;
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wenzelm@32122
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val valid = not (Task_Queue.is_canceled group);
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wenzelm@42541
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val ok =
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wenzelm@42541
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Task_Queue.running task (fn () =>
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wenzelm@42563
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setmp_worker_task task (fn () =>
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wenzelm@42541
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fold (fn job => fn ok => job valid andalso ok) jobs true) ());
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wenzelm@42647
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val _ = Multithreading.tracing 2 (fn () =>
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wenzelm@42541
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let
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wenzelm@44823
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val s = Task_Queue.str_of_task_groups task;
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wenzelm@42541
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fun micros time = string_of_int (Time.toNanoseconds time div 1000);
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wenzelm@42560
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val (run, wait, deps) = Task_Queue.timing_of_task task;
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wenzelm@42560
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in "TASK " ^ s ^ " " ^ micros run ^ " " ^ micros wait ^ " (" ^ commas deps ^ ")" end);
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wenzelm@32250
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val _ = SYNCHRONIZED "finish" (fn () =>
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wenzelm@32219
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let
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wenzelm@32738
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val maximal = Unsynchronized.change_result queue (Task_Queue.finish task);
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wenzelm@44994
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val _ = Exn.capture Multithreading.interrupted ();
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wenzelm@32219
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val _ =
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wenzelm@32219
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if ok then ()
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wenzelm@34279
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else if cancel_now group then ()
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wenzelm@34279
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else cancel_later group;
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wenzelm@32219
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val _ = broadcast work_finished;
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wenzelm@33434
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val _ = if maximal then () else signal work_available;
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wenzelm@32219
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in () end);
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wenzelm@28167
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in () end;
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wenzelm@28167
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wenzelm@33431
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fun worker_wait active cond = (*requires SYNCHRONIZED*)
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wenzelm@33427
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let
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wenzelm@33431
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val state =
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wenzelm@33431
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(case AList.lookup Thread.equal (! workers) (Thread.self ()) of
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wenzelm@33431
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SOME state => state
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wenzelm@33431
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| NONE => raise Fail "Unregistered worker thread");
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wenzelm@33431
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val _ = state := (if active then Waiting else Sleeping);
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wenzelm@33427
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val _ = wait cond;
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wenzelm@33431
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val _ = state := Working;
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wenzelm@33427
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in () end;
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wenzelm@28162
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wenzelm@33436
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fun worker_next () = (*requires SYNCHRONIZED*)
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wenzelm@33427
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if length (! workers) > ! max_workers then
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wenzelm@33427
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(Unsynchronized.change workers (AList.delete Thread.equal (Thread.self ()));
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wenzelm@33436
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signal work_available;
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wenzelm@28167
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NONE)
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wenzelm@33431
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else if count_workers Working > ! max_active then
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wenzelm@33436
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(worker_wait false work_available; worker_next ())
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wenzelm@28166
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else
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wenzelm@32738
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(case Unsynchronized.change_result queue (Task_Queue.dequeue (Thread.self ())) of
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wenzelm@33436
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NONE => (worker_wait false work_available; worker_next ())
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wenzelm@33434
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| some => (signal work_available; some));
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wenzelm@28156
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wenzelm@28167
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fun worker_loop name =
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wenzelm@33436
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(case SYNCHRONIZED name (fn () => worker_next ()) of
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wenzelm@29120
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NONE => ()
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wenzelm@44993
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| SOME work => (Exn.capture Multithreading.interrupted (); worker_exec work; worker_loop name));
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wenzelm@28156
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wenzelm@33428
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fun worker_start name = (*requires SYNCHRONIZED*)
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wenzelm@37216
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Unsynchronized.change workers (cons (Simple_Thread.fork false (fn () => worker_loop name),
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wenzelm@33431
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Unsynchronized.ref Working));
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wenzelm@28156
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wenzelm@28156
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wenzelm@28156
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(* scheduler *)
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wenzelm@28156
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wenzelm@33428
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val status_ticks = Unsynchronized.ref 0;
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wenzelm@33428
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wenzelm@33428
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val last_round = Unsynchronized.ref Time.zeroTime;
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wenzelm@40553
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val next_round = seconds 0.05;
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wenzelm@32226
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wenzelm@28206
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fun scheduler_next () = (*requires SYNCHRONIZED*)
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wenzelm@28156
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let
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wenzelm@33428
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val now = Time.now ();
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wenzelm@33428
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val tick = Time.<= (Time.+ (! last_round, next_round), now);
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wenzelm@33428
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val _ = if tick then last_round := now else ();
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wenzelm@33428
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wenzelm@33436
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wenzelm@33436
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(* queue and worker status *)
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wenzelm@33436
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wenzelm@32226
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val _ =
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wenzelm@33428
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if tick then Unsynchronized.change status_ticks (fn i => (i + 1) mod 10) else ();
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wenzelm@33428
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val _ =
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wenzelm@33428
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if tick andalso ! status_ticks = 0 then
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wenzelm@33428
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262 |
Multithreading.tracing 1 (fn () =>
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wenzelm@33428
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263 |
let
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wenzelm@34277
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264 |
val {ready, pending, running, passive} = Task_Queue.status (! queue);
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wenzelm@33428
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265 |
val total = length (! workers);
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wenzelm@33431
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val active = count_workers Working;
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wenzelm@33431
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val waiting = count_workers Waiting;
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wenzelm@33428
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in
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wenzelm@33428
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"SCHEDULE " ^ Time.toString now ^ ": " ^
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wenzelm@33428
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string_of_int ready ^ " ready, " ^
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wenzelm@33428
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string_of_int pending ^ " pending, " ^
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wenzelm@34277
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string_of_int running ^ " running, " ^
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wenzelm@34277
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string_of_int passive ^ " passive; " ^
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wenzelm@33428
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string_of_int total ^ " workers, " ^
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wenzelm@33431
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string_of_int active ^ " active, " ^
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wenzelm@33431
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string_of_int waiting ^ " waiting "
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wenzelm@33428
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end)
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wenzelm@33428
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else ();
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wenzelm@32053
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wenzelm@28191
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280 |
val _ =
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wenzelm@32219
|
281 |
if forall (Thread.isActive o #1) (! workers) then ()
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wenzelm@32115
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else
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wenzelm@33430
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283 |
let
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wenzelm@37698
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val (alive, dead) = List.partition (Thread.isActive o #1) (! workers);
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wenzelm@33430
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285 |
val _ = workers := alive;
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wenzelm@33430
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286 |
in
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wenzelm@33430
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287 |
Multithreading.tracing 0 (fn () =>
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wenzelm@33430
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288 |
"SCHEDULE: disposed " ^ string_of_int (length dead) ^ " dead worker threads")
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wenzelm@33430
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289 |
end;
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wenzelm@28191
|
290 |
|
wenzelm@33436
|
291 |
|
wenzelm@33436
|
292 |
(* worker pool adjustments *)
|
wenzelm@33436
|
293 |
|
wenzelm@33436
|
294 |
val max_active0 = ! max_active;
|
wenzelm@33436
|
295 |
val max_workers0 = ! max_workers;
|
wenzelm@33436
|
296 |
|
wenzelm@28206
|
297 |
val m = if ! do_shutdown then 0 else Multithreading.max_threads_value ();
|
wenzelm@33427
|
298 |
val _ = max_active := m;
|
wenzelm@33427
|
299 |
|
wenzelm@33432
|
300 |
val mm =
|
wenzelm@33432
|
301 |
if ! do_shutdown then 0
|
wenzelm@33432
|
302 |
else if m = 9999 then 1
|
wenzelm@33434
|
303 |
else Int.min (Int.max (count_workers Working + 2 * count_workers Waiting, m), 4 * m);
|
wenzelm@33432
|
304 |
val _ =
|
wenzelm@33432
|
305 |
if tick andalso mm > ! max_workers then
|
wenzelm@33432
|
306 |
Unsynchronized.change worker_trend (fn w => if w < 0 then 0 else w + 1)
|
wenzelm@33432
|
307 |
else if tick andalso mm < ! max_workers then
|
wenzelm@33432
|
308 |
Unsynchronized.change worker_trend (fn w => if w > 0 then 0 else w - 1)
|
wenzelm@33432
|
309 |
else ();
|
wenzelm@33432
|
310 |
val _ =
|
wenzelm@33436
|
311 |
if mm = 0 orelse ! worker_trend > 50 orelse ! worker_trend < ~50 then
|
wenzelm@33436
|
312 |
max_workers := mm
|
wenzelm@33436
|
313 |
else if ! worker_trend > 5 andalso ! max_workers < 2 * m then
|
wenzelm@33436
|
314 |
max_workers := Int.min (mm, 2 * m)
|
wenzelm@33432
|
315 |
else ();
|
wenzelm@33427
|
316 |
|
wenzelm@33428
|
317 |
val missing = ! max_workers - length (! workers);
|
wenzelm@28203
|
318 |
val _ =
|
wenzelm@33428
|
319 |
if missing > 0 then
|
wenzelm@33436
|
320 |
funpow missing (fn () =>
|
wenzelm@33436
|
321 |
ignore (worker_start ("worker " ^ string_of_int (Unsynchronized.inc next)))) ()
|
wenzelm@28203
|
322 |
else ();
|
wenzelm@28206
|
323 |
|
wenzelm@33436
|
324 |
val _ =
|
wenzelm@33436
|
325 |
if ! max_active = max_active0 andalso ! max_workers = max_workers0 then ()
|
wenzelm@33436
|
326 |
else signal work_available;
|
wenzelm@33436
|
327 |
|
wenzelm@33436
|
328 |
|
wenzelm@33436
|
329 |
(* canceled groups *)
|
wenzelm@33436
|
330 |
|
wenzelm@32225
|
331 |
val _ =
|
wenzelm@32225
|
332 |
if null (! canceled) then ()
|
wenzelm@32293
|
333 |
else
|
wenzelm@32293
|
334 |
(Multithreading.tracing 1 (fn () =>
|
wenzelm@32293
|
335 |
string_of_int (length (! canceled)) ^ " canceled groups");
|
wenzelm@34279
|
336 |
Unsynchronized.change canceled (filter_out cancel_now);
|
wenzelm@32293
|
337 |
broadcast_work ());
|
wenzelm@28206
|
338 |
|
wenzelm@33436
|
339 |
|
wenzelm@33436
|
340 |
(* delay loop *)
|
wenzelm@33436
|
341 |
|
wenzelm@32298
|
342 |
val _ = Exn.release (wait_timeout next_round scheduler_event);
|
wenzelm@32219
|
343 |
|
wenzelm@33436
|
344 |
|
wenzelm@33436
|
345 |
(* shutdown *)
|
wenzelm@33436
|
346 |
|
wenzelm@34277
|
347 |
val _ = if Task_Queue.all_passive (! queue) then do_shutdown := true else ();
|
wenzelm@32219
|
348 |
val continue = not (! do_shutdown andalso null (! workers));
|
wenzelm@28206
|
349 |
val _ = if continue then () else scheduler := NONE;
|
wenzelm@33436
|
350 |
|
wenzelm@32219
|
351 |
val _ = broadcast scheduler_event;
|
wenzelm@32298
|
352 |
in continue end
|
wenzelm@39509
|
353 |
handle exn =>
|
wenzelm@39509
|
354 |
if Exn.is_interrupt exn then
|
wenzelm@39509
|
355 |
(Multithreading.tracing 1 (fn () => "Interrupt");
|
wenzelm@39509
|
356 |
List.app cancel_later (Task_Queue.cancel_all (! queue));
|
wenzelm@39509
|
357 |
broadcast_work (); true)
|
wenzelm@39509
|
358 |
else reraise exn;
|
wenzelm@32298
|
359 |
|
wenzelm@28206
|
360 |
fun scheduler_loop () =
|
wenzelm@33437
|
361 |
while
|
wenzelm@33437
|
362 |
Multithreading.with_attributes
|
wenzelm@33437
|
363 |
(Multithreading.sync_interrupts Multithreading.public_interrupts)
|
wenzelm@33437
|
364 |
(fn _ => SYNCHRONIZED "scheduler" (fn () => scheduler_next ()))
|
wenzelm@33437
|
365 |
do ();
|
wenzelm@28191
|
366 |
|
wenzelm@28203
|
367 |
fun scheduler_active () = (*requires SYNCHRONIZED*)
|
wenzelm@28203
|
368 |
(case ! scheduler of NONE => false | SOME thread => Thread.isActive thread);
|
wenzelm@28203
|
369 |
|
wenzelm@32228
|
370 |
fun scheduler_check () = (*requires SYNCHRONIZED*)
|
wenzelm@32228
|
371 |
(do_shutdown := false;
|
wenzelm@32252
|
372 |
if scheduler_active () then ()
|
wenzelm@37216
|
373 |
else scheduler := SOME (Simple_Thread.fork false scheduler_loop));
|
wenzelm@28191
|
374 |
|
wenzelm@28191
|
375 |
|
wenzelm@28191
|
376 |
|
wenzelm@29370
|
377 |
(** futures **)
|
wenzelm@29370
|
378 |
|
wenzelm@44993
|
379 |
(* cancellation *)
|
wenzelm@44993
|
380 |
|
wenzelm@44993
|
381 |
(*cancel: present and future group members will be interrupted eventually*)
|
wenzelm@44993
|
382 |
fun cancel_group group = SYNCHRONIZED "cancel" (fn () =>
|
wenzelm@44993
|
383 |
(if cancel_now group then () else cancel_later group;
|
wenzelm@44993
|
384 |
signal work_available; scheduler_check ()));
|
wenzelm@44993
|
385 |
|
wenzelm@44993
|
386 |
fun cancel x = cancel_group (Task_Queue.group_of_task (task_of x));
|
wenzelm@44993
|
387 |
|
wenzelm@44993
|
388 |
|
wenzelm@44993
|
389 |
(* future jobs *)
|
wenzelm@44993
|
390 |
|
wenzelm@44993
|
391 |
fun assign_result group result res =
|
wenzelm@44993
|
392 |
let
|
wenzelm@44993
|
393 |
val _ = Single_Assignment.assign result res
|
wenzelm@44993
|
394 |
handle exn as Fail _ =>
|
wenzelm@44993
|
395 |
(case Single_Assignment.peek result of
|
wenzelm@44993
|
396 |
SOME (Exn.Exn e) => reraise (if Exn.is_interrupt e then e else exn)
|
wenzelm@44993
|
397 |
| _ => reraise exn);
|
wenzelm@44993
|
398 |
val ok =
|
wenzelm@44993
|
399 |
(case the (Single_Assignment.peek result) of
|
wenzelm@44994
|
400 |
Exn.Exn exn =>
|
wenzelm@44994
|
401 |
(SYNCHRONIZED "cancel" (fn () => Task_Queue.cancel_group group exn); false)
|
wenzelm@44993
|
402 |
| Exn.Res _ => true);
|
wenzelm@44993
|
403 |
in ok end;
|
wenzelm@44993
|
404 |
|
wenzelm@44996
|
405 |
fun future_job group interrupts (e: unit -> 'a) =
|
wenzelm@44993
|
406 |
let
|
wenzelm@44993
|
407 |
val result = Single_Assignment.var "future" : 'a result;
|
wenzelm@44993
|
408 |
val pos = Position.thread_data ();
|
wenzelm@44993
|
409 |
fun job ok =
|
wenzelm@44993
|
410 |
let
|
wenzelm@44993
|
411 |
val res =
|
wenzelm@44993
|
412 |
if ok then
|
wenzelm@44993
|
413 |
Exn.capture (fn () =>
|
wenzelm@44996
|
414 |
Multithreading.with_attributes
|
wenzelm@44996
|
415 |
(if interrupts
|
wenzelm@44996
|
416 |
then Multithreading.private_interrupts else Multithreading.no_interrupts)
|
wenzelm@44993
|
417 |
(fn _ => Position.setmp_thread_data pos e ()) before
|
wenzelm@44993
|
418 |
Multithreading.interrupted ()) ()
|
wenzelm@44993
|
419 |
else Exn.interrupt_exn;
|
wenzelm@44993
|
420 |
in assign_result group result res end;
|
wenzelm@44993
|
421 |
in (result, job) end;
|
wenzelm@44993
|
422 |
|
wenzelm@44993
|
423 |
|
wenzelm@29370
|
424 |
(* fork *)
|
wenzelm@29370
|
425 |
|
wenzelm@44996
|
426 |
type fork_params =
|
wenzelm@44996
|
427 |
{name: string, group: Task_Queue.group option, deps: Task_Queue.task list,
|
wenzelm@44996
|
428 |
pri: int, interrupts: bool};
|
wenzelm@44996
|
429 |
|
wenzelm@44996
|
430 |
fun forks ({name, group, deps, pri, interrupts}: fork_params) es =
|
wenzelm@42545
|
431 |
if null es then []
|
wenzelm@42545
|
432 |
else
|
wenzelm@42545
|
433 |
let
|
wenzelm@42545
|
434 |
val grp =
|
wenzelm@42545
|
435 |
(case group of
|
wenzelm@42545
|
436 |
NONE => worker_subgroup ()
|
wenzelm@42545
|
437 |
| SOME grp => grp);
|
wenzelm@42579
|
438 |
fun enqueue e queue =
|
wenzelm@42545
|
439 |
let
|
wenzelm@44996
|
440 |
val (result, job) = future_job grp interrupts e;
|
wenzelm@42579
|
441 |
val (task, queue') = Task_Queue.enqueue name grp deps pri job queue;
|
wenzelm@42563
|
442 |
val future = Future {promised = false, task = task, result = result};
|
wenzelm@42579
|
443 |
in (future, queue') end;
|
wenzelm@42545
|
444 |
in
|
wenzelm@42545
|
445 |
SYNCHRONIZED "enqueue" (fn () =>
|
wenzelm@42545
|
446 |
let
|
wenzelm@42579
|
447 |
val (futures, queue') = fold_map enqueue es (! queue);
|
wenzelm@42579
|
448 |
val _ = queue := queue';
|
wenzelm@42579
|
449 |
val minimal = forall (not o Task_Queue.known_task queue') deps;
|
wenzelm@42545
|
450 |
val _ = if minimal then signal work_available else ();
|
wenzelm@42545
|
451 |
val _ = scheduler_check ();
|
wenzelm@42545
|
452 |
in futures end)
|
wenzelm@42545
|
453 |
end;
|
wenzelm@28162
|
454 |
|
wenzelm@44996
|
455 |
fun fork_pri pri e =
|
wenzelm@44996
|
456 |
singleton (forks {name = "", group = NONE, deps = [], pri = pri, interrupts = true}) e;
|
wenzelm@44996
|
457 |
|
wenzelm@42543
|
458 |
fun fork e = fork_pri 0 e;
|
wenzelm@28162
|
459 |
|
wenzelm@28186
|
460 |
|
wenzelm@29370
|
461 |
(* join *)
|
wenzelm@28186
|
462 |
|
wenzelm@29551
|
463 |
local
|
wenzelm@29551
|
464 |
|
wenzelm@32119
|
465 |
fun get_result x =
|
wenzelm@32119
|
466 |
(case peek x of
|
wenzelm@38120
|
467 |
NONE => Exn.Exn (Fail "Unfinished future")
|
wenzelm@39509
|
468 |
| SOME res =>
|
wenzelm@39509
|
469 |
if Exn.is_interrupt_exn res then
|
wenzelm@42563
|
470 |
(case Exn.flatten_list (Task_Queue.group_status (Task_Queue.group_of_task (task_of x))) of
|
wenzelm@39509
|
471 |
[] => res
|
wenzelm@39509
|
472 |
| exns => Exn.Exn (Exn.EXCEPTIONS exns))
|
wenzelm@39509
|
473 |
else res);
|
wenzelm@28177
|
474 |
|
wenzelm@32115
|
475 |
fun join_next deps = (*requires SYNCHRONIZED*)
|
wenzelm@42566
|
476 |
if null deps then NONE
|
wenzelm@32224
|
477 |
else
|
wenzelm@42561
|
478 |
(case Unsynchronized.change_result queue (Task_Queue.dequeue_deps (Thread.self ()) deps) of
|
wenzelm@42566
|
479 |
(NONE, []) => NONE
|
wenzelm@42566
|
480 |
| (NONE, deps') =>
|
wenzelm@42566
|
481 |
(worker_waiting deps' (fn () => worker_wait true work_finished); join_next deps')
|
wenzelm@32224
|
482 |
| (SOME work, deps') => SOME (work, deps'));
|
wenzelm@32115
|
483 |
|
wenzelm@32823
|
484 |
fun execute_work NONE = ()
|
wenzelm@44993
|
485 |
| execute_work (SOME (work, deps')) =
|
wenzelm@44993
|
486 |
(worker_joining (fn () => worker_exec work); join_work deps')
|
wenzelm@32823
|
487 |
and join_work deps =
|
wenzelm@44409
|
488 |
Multithreading.with_attributes Multithreading.no_interrupts
|
wenzelm@44409
|
489 |
(fn _ => execute_work (SYNCHRONIZED "join" (fn () => join_next deps)));
|
wenzelm@32823
|
490 |
|
wenzelm@29551
|
491 |
in
|
wenzelm@29551
|
492 |
|
wenzelm@29370
|
493 |
fun join_results xs =
|
wenzelm@42559
|
494 |
let
|
wenzelm@42559
|
495 |
val _ =
|
wenzelm@42559
|
496 |
if forall is_finished xs then ()
|
wenzelm@42559
|
497 |
else if Multithreading.self_critical () then
|
wenzelm@42559
|
498 |
error "Cannot join future values within critical section"
|
wenzelm@42566
|
499 |
else if is_some (worker_task ()) then join_work (map task_of xs)
|
wenzelm@42561
|
500 |
else List.app (ignore o Single_Assignment.await o result_of) xs;
|
wenzelm@42559
|
501 |
in map get_result xs end;
|
wenzelm@28186
|
502 |
|
wenzelm@29551
|
503 |
end;
|
wenzelm@29551
|
504 |
|
wenzelm@28647
|
505 |
fun join_result x = singleton join_results x;
|
wenzelm@28647
|
506 |
fun join x = Exn.release (join_result x);
|
wenzelm@28156
|
507 |
|
wenzelm@28979
|
508 |
|
wenzelm@44993
|
509 |
(* fast-path versions -- bypassing task queue *)
|
wenzelm@34277
|
510 |
|
wenzelm@34277
|
511 |
fun value (x: 'a) =
|
wenzelm@34277
|
512 |
let
|
wenzelm@42563
|
513 |
val task = Task_Queue.dummy_task ();
|
wenzelm@42563
|
514 |
val group = Task_Queue.group_of_task task;
|
wenzelm@35016
|
515 |
val result = Single_Assignment.var "value" : 'a result;
|
wenzelm@44633
|
516 |
val _ = assign_result group result (Exn.Res x);
|
wenzelm@42563
|
517 |
in Future {promised = false, task = task, result = result} end;
|
wenzelm@28191
|
518 |
|
wenzelm@29384
|
519 |
fun map_future f x =
|
wenzelm@29370
|
520 |
let
|
wenzelm@29384
|
521 |
val task = task_of x;
|
wenzelm@42563
|
522 |
val group = Task_Queue.new_group (SOME (Task_Queue.group_of_task task));
|
wenzelm@44996
|
523 |
val (result, job) = future_job group true (fn () => f (join x));
|
wenzelm@29384
|
524 |
|
wenzelm@32250
|
525 |
val extended = SYNCHRONIZED "extend" (fn () =>
|
wenzelm@29370
|
526 |
(case Task_Queue.extend task job (! queue) of
|
wenzelm@29370
|
527 |
SOME queue' => (queue := queue'; true)
|
wenzelm@29370
|
528 |
| NONE => false));
|
wenzelm@29370
|
529 |
in
|
wenzelm@42563
|
530 |
if extended then Future {promised = false, task = task, result = result}
|
wenzelm@42543
|
531 |
else
|
wenzelm@42544
|
532 |
singleton
|
wenzelm@44996
|
533 |
(forks {name = "Future.map", group = SOME group, deps = [task],
|
wenzelm@44996
|
534 |
pri = Task_Queue.pri_of_task task, interrupts = true})
|
wenzelm@42543
|
535 |
(fn () => f (join x))
|
wenzelm@29370
|
536 |
end;
|
wenzelm@29370
|
537 |
|
wenzelm@42999
|
538 |
fun cond_forks args es =
|
wenzelm@42999
|
539 |
if Multithreading.enabled () then forks args es
|
wenzelm@42999
|
540 |
else map (fn e => value (e ())) es;
|
wenzelm@42999
|
541 |
|
wenzelm@29370
|
542 |
|
wenzelm@34277
|
543 |
(* promised futures -- fulfilled by external means *)
|
wenzelm@34277
|
544 |
|
wenzelm@34277
|
545 |
fun promise_group group : 'a future =
|
wenzelm@34277
|
546 |
let
|
wenzelm@35016
|
547 |
val result = Single_Assignment.var "promise" : 'a result;
|
wenzelm@39520
|
548 |
fun abort () = assign_result group result Exn.interrupt_exn
|
wenzelm@39520
|
549 |
handle Fail _ => true
|
wenzelm@39520
|
550 |
| exn =>
|
wenzelm@39520
|
551 |
if Exn.is_interrupt exn then raise Fail "Concurrent attempt to fulfill promise"
|
wenzelm@39520
|
552 |
else reraise exn;
|
wenzelm@38122
|
553 |
val task = SYNCHRONIZED "enqueue_passive" (fn () =>
|
wenzelm@38122
|
554 |
Unsynchronized.change_result queue (Task_Queue.enqueue_passive group abort));
|
wenzelm@42563
|
555 |
in Future {promised = true, task = task, result = result} end;
|
wenzelm@34277
|
556 |
|
wenzelm@38133
|
557 |
fun promise () = promise_group (worker_subgroup ());
|
wenzelm@34277
|
558 |
|
wenzelm@42563
|
559 |
fun fulfill_result (Future {promised, task, result}) res =
|
wenzelm@39520
|
560 |
if not promised then raise Fail "Not a promised future"
|
wenzelm@39520
|
561 |
else
|
wenzelm@39520
|
562 |
let
|
wenzelm@42563
|
563 |
val group = Task_Queue.group_of_task task;
|
wenzelm@39520
|
564 |
fun job ok = assign_result group result (if ok then res else Exn.interrupt_exn);
|
wenzelm@39520
|
565 |
val _ =
|
wenzelm@39520
|
566 |
Multithreading.with_attributes Multithreading.no_interrupts (fn _ =>
|
wenzelm@39520
|
567 |
let
|
wenzelm@39520
|
568 |
val still_passive =
|
wenzelm@39520
|
569 |
SYNCHRONIZED "fulfill_result" (fn () =>
|
wenzelm@39520
|
570 |
Unsynchronized.change_result queue
|
wenzelm@39520
|
571 |
(Task_Queue.dequeue_passive (Thread.self ()) task));
|
wenzelm@44993
|
572 |
in if still_passive then worker_exec (task, [job]) else () end);
|
wenzelm@42561
|
573 |
val _ =
|
wenzelm@42566
|
574 |
if is_some (Single_Assignment.peek result) then ()
|
wenzelm@42566
|
575 |
else worker_waiting [task] (fn () => ignore (Single_Assignment.await result));
|
wenzelm@39520
|
576 |
in () end;
|
wenzelm@34277
|
577 |
|
wenzelm@44633
|
578 |
fun fulfill x res = fulfill_result x (Exn.Res res);
|
wenzelm@34277
|
579 |
|
wenzelm@34277
|
580 |
|
wenzelm@32228
|
581 |
(* shutdown *)
|
wenzelm@29370
|
582 |
|
wenzelm@28203
|
583 |
fun shutdown () =
|
wenzelm@28276
|
584 |
if Multithreading.available then
|
wenzelm@28276
|
585 |
SYNCHRONIZED "shutdown" (fn () =>
|
wenzelm@32228
|
586 |
while scheduler_active () do
|
wenzelm@34279
|
587 |
(wait scheduler_event; broadcast_work ()))
|
wenzelm@28276
|
588 |
else ();
|
wenzelm@28203
|
589 |
|
wenzelm@29370
|
590 |
|
wenzelm@38492
|
591 |
(* status markup *)
|
wenzelm@37706
|
592 |
|
wenzelm@38492
|
593 |
fun status e =
|
wenzelm@37706
|
594 |
let
|
wenzelm@40705
|
595 |
val task_props =
|
wenzelm@40705
|
596 |
(case worker_task () of
|
wenzelm@40705
|
597 |
NONE => I
|
wenzelm@40705
|
598 |
| SOME task => Markup.properties [(Markup.taskN, Task_Queue.str_of_task task)]);
|
wenzelm@44540
|
599 |
val _ = Output.status (Markup.markup_only (task_props Markup.forked));
|
wenzelm@37706
|
600 |
val x = e (); (*sic -- report "joined" only for success*)
|
wenzelm@44540
|
601 |
val _ = Output.status (Markup.markup_only (task_props Markup.joined));
|
wenzelm@37706
|
602 |
in x end;
|
wenzelm@37706
|
603 |
|
wenzelm@37706
|
604 |
|
wenzelm@29370
|
605 |
(*final declarations of this structure!*)
|
wenzelm@29370
|
606 |
val map = map_future;
|
wenzelm@29370
|
607 |
|
wenzelm@28156
|
608 |
end;
|
wenzelm@28972
|
609 |
|
wenzelm@28972
|
610 |
type 'a future = 'a Future.future;
|
wenzelm@28972
|
611 |
|