Quellcode-Bibliothek

^© Kompilation durch diese Firma

[Weder Korrektheit noch Funktionsfähigkeit der Software werden zugesichert.]

Datei: multithreading.ML Sprache: SML

Original von: Isabelle^©

(*  Title:      Pure/Concurrent/multithreading.ML
    Author:     Makarius

Multithreading in Poly/ML (cf. polyml/basis/Thread.sml).
*)

signature MULTITHREADING =
sig
  val max_threads: unit -> int
  val max_threads_update: int -> unit
  val parallel_proofs: int ref
  val sync_wait: Time.time option -> ConditionVar.conditionVar -> Mutex.mutex -> bool Exn.result
  val trace: int ref
  val tracing: int -> (unit -> string) -> unit
  val tracing_time: bool -> Time.time -> (unit -> string) -> unit
  val synchronized: string -> Mutex.mutex -> (unit -> 'a) -> 'a
end;

structure Multithreading: MULTITHREADING =
struct

(* max_threads *)

local

fun num_processors () =
  (case Thread.numPhysicalProcessors () of
    SOME n => n
  | NONE => Thread.numProcessors ());

fun max_threads_result m =
  if Thread_Data.is_virtual then 1
  else if m > 0 then m
  else Int.min (Int.max (num_processors (), 1), 8);

val max_threads_state = ref 1;

in

fun max_threads () = ! max_threads_state;
fun max_threads_update m = max_threads_state := max_threads_result m;

end;

(* parallel_proofs *)

val parallel_proofs = ref 1;

(* synchronous wait *)

fun sync_wait time cond lock =
  Thread_Attributes.with_attributes
    (Thread_Attributes.sync_interrupts (Thread_Attributes.get_attributes ()))
    (fn _ =>
      (case time of
        SOME t => Exn.Res (ConditionVar.waitUntil (cond, lock, t))
      | NONE => (ConditionVar.wait (cond, lock); Exn.Res true))
      handle exn => Exn.Exn exn);

(* tracing *)

val trace = ref 0;

fun tracing level msg =
  if ! trace < level then ()
  else Thread_Attributes.uninterruptible (fn _ => fn () =>
    (TextIO.output (TextIO.stdErr, (">>> " ^ msg () ^ "\n")); TextIO.flushOut TextIO.stdErr)
      handle _ (*sic*) => ()) ();

fun tracing_time detailed time =
  tracing
   (if not detailed then 5
    else if time >= seconds 1.0 then 1
    else if time >= seconds 0.1 then 2
    else if time >= seconds 0.01 then 3
    else if time >= seconds 0.001 then 4 else 5);

(* synchronized evaluation *)

fun synchronized name lock e =
  Exn.release (Thread_Attributes.uninterruptible (fn restore_attributes => fn () =>
    if ! trace > 0 then
      let
        val immediate =
          if Mutex.trylock lock then true
          else
            let
              val _ = tracing 5 (fn () => name ^ ": locking ...");
              val timer = Timer.startRealTimer ();
              val _ = Mutex.lock lock;
              val time = Timer.checkRealTimer timer;
              val _ = tracing_time true time (fn () => name ^ ": locked after " ^ Time.toString time);
            in false end;
        val result = Exn.capture (restore_attributes e) ();
        val _ = if immediate then () else tracing 5 (fn () => name ^ ": unlocking ...");
        val _ = Mutex.unlock lock;
      in result end
    else
      let
        val _ = Mutex.lock lock;
        val result = Exn.capture (restore_attributes e) ();
        val _ = Mutex.unlock lock;
      in result end) ());

end;

¤ Dauer der Verarbeitung: 0.3 Sekunden (vorverarbeitet) ¤

Download des Quellennavigators
Download des sprechenden Kalenders
in der Quellcodebibliothek suchen

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.