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dc2a560264
* libguile/root.h: * libguile/root.c: Remove these files. * libguile/deprecated.h: * libguile/deprecated.c (scm_internal_cwdr, scm_call_with_dynamic_root) (scm_dynamic_root, scm_apply_with_dynamic_root): Deprecate. Remove all root.h usage, which was vestigial. * module/ice-9/serialize.scm: Use (current-thread) instead of (dynamic-root).
114 lines
3.8 KiB
Scheme
114 lines
3.8 KiB
Scheme
;;;; Copyright (C) 2003, 2006 Free Software Foundation, Inc.
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;;;;
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;;;; This library is free software; you can redistribute it and/or
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;;;; modify it under the terms of the GNU Lesser General Public
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;;;; License as published by the Free Software Foundation; either
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;;;; version 3 of the License, or (at your option) any later version.
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;;;;
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;;;; This library is distributed in the hope that it will be useful,
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;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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;;;; Lesser General Public License for more details.
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;;;;
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;;;; You should have received a copy of the GNU Lesser General Public
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;;;; License along with this library; if not, write to the Free Software
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;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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;;;;
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;;; Commentary:
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;; (serialize FORM1 ...) and (parallelize FORM1 ...) are useful when
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;; you don't trust the thread safety of most of your program, but
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;; where you have some section(s) of code which you consider can run
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;; in parallel to other sections.
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;;
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;; They "flag" (with dynamic extent) sections of code to be of
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;; "serial" or "parallel" nature and have the single effect of
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;; preventing a serial section from being run in parallel with any
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;; serial section (including itself).
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;;
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;; Both serialize and parallelize can be nested. If so, the
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;; inner-most construct is in effect.
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;;
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;; NOTE 1: A serial section can run in parallel with a parallel
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;; section.
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;;
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;; NOTE 2: If a serial section S is "interrupted" by a parallel
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;; section P in the following manner: S = S1 P S2, S2 is not
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;; guaranteed to be resumed by the same thread that previously
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;; executed S1.
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;;
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;; WARNING: Spawning new threads within a serial section have
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;; undefined effects. It is OK, though, to spawn threads in unflagged
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;; sections of code where neither serialize or parallelize is in
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;; effect.
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;;
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;; A typical usage is when Guile is used as scripting language in some
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;; application doing heavy computations. If each thread is
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;; encapsulated with a serialize form, you can then put a parallelize
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;; form around the code performing the heavy computations (typically a
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;; C code primitive), enabling the computations to run in parallel
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;; while the scripting code runs single-threadedly.
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;;
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;;; Code:
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(define-module (ice-9 serialize)
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:use-module (ice-9 threads)
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:export (call-with-serialization
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call-with-parallelization)
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:export-syntax (serialize
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parallelize))
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(define serialization-mutex (make-mutex))
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(define admin-mutex (make-mutex))
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(define owner #f)
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(define (call-with-serialization thunk)
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(let ((outer-owner #f))
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(dynamic-wind
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(lambda ()
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(lock-mutex admin-mutex)
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(set! outer-owner owner)
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(if (not (eqv? outer-owner (current-thread)))
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(begin
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(unlock-mutex admin-mutex)
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(lock-mutex serialization-mutex)
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(set! owner (current-thread)))
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(unlock-mutex admin-mutex)))
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thunk
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(lambda ()
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(lock-mutex admin-mutex)
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(if (not (eqv? outer-owner (current-thread)))
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(begin
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(set! owner #f)
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(unlock-mutex serialization-mutex)))
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(unlock-mutex admin-mutex)))))
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(define-macro (serialize . forms)
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`(call-with-serialization (lambda () ,@forms)))
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(define (call-with-parallelization thunk)
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(let ((outer-owner #f))
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(dynamic-wind
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(lambda ()
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(lock-mutex admin-mutex)
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(set! outer-owner owner)
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(if (eqv? outer-owner (current-thread))
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(begin
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(set! owner #f)
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(unlock-mutex serialization-mutex)))
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(unlock-mutex admin-mutex))
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thunk
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(lambda ()
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(lock-mutex admin-mutex)
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(if (eqv? outer-owner (current-thread))
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(begin
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(unlock-mutex admin-mutex)
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(lock-mutex serialization-mutex)
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(set! owner outer-owner))
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(unlock-mutex admin-mutex))))))
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(define-macro (parallelize . forms)
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`(call-with-parallelization (lambda () ,@forms)))
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