/usr/share/guile/1.8/ice-9/serialize.scm is in guile-1.8-libs 1.8.8+1-6ubuntu2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 | ;;;; Copyright (C) 2003, 2006 Free Software Foundation, Inc.
;;;;
;;;; This library is free software; you can redistribute it and/or
;;;; modify it under the terms of the GNU Lesser General Public
;;;; License as published by the Free Software Foundation; either
;;;; version 2.1 of the License, or (at your option) any later version.
;;;;
;;;; This library is distributed in the hope that it will be useful,
;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;;;; Lesser General Public License for more details.
;;;;
;;;; You should have received a copy of the GNU Lesser General Public
;;;; License along with this library; if not, write to the Free Software
;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;;;;
;;; Commentary:
;; (serialize FORM1 ...) and (parallelize FORM1 ...) are useful when
;; you don't trust the thread safety of most of your program, but
;; where you have some section(s) of code which you consider can run
;; in parallel to other sections.
;;
;; They "flag" (with dynamic extent) sections of code to be of
;; "serial" or "parallel" nature and have the single effect of
;; preventing a serial section from being run in parallel with any
;; serial section (including itself).
;;
;; Both serialize and parallelize can be nested. If so, the
;; inner-most construct is in effect.
;;
;; NOTE 1: A serial section can run in parallel with a parallel
;; section.
;;
;; NOTE 2: If a serial section S is "interrupted" by a parallel
;; section P in the following manner: S = S1 P S2, S2 is not
;; guaranteed to be resumed by the same thread that previously
;; executed S1.
;;
;; WARNING: Spawning new threads within a serial section have
;; undefined effects. It is OK, though, to spawn threads in unflagged
;; sections of code where neither serialize or parallelize is in
;; effect.
;;
;; A typical usage is when Guile is used as scripting language in some
;; application doing heavy computations. If each thread is
;; encapsulated with a serialize form, you can then put a parallelize
;; form around the code performing the heavy computations (typically a
;; C code primitive), enabling the computations to run in parallel
;; while the scripting code runs single-threadedly.
;;
;;; Code:
(define-module (ice-9 serialize)
:use-module (ice-9 threads)
:export (call-with-serialization
call-with-parallelization)
:export-syntax (serialize
parallelize))
(define serialization-mutex (make-mutex))
(define admin-mutex (make-mutex))
(define owner #f)
(define (call-with-serialization thunk)
(let ((outer-owner #f))
(dynamic-wind
(lambda ()
(lock-mutex admin-mutex)
(set! outer-owner owner)
(if (not (eqv? outer-owner (dynamic-root)))
(begin
(unlock-mutex admin-mutex)
(lock-mutex serialization-mutex)
(set! owner (dynamic-root)))
(unlock-mutex admin-mutex)))
thunk
(lambda ()
(lock-mutex admin-mutex)
(if (not (eqv? outer-owner (dynamic-root)))
(begin
(set! owner #f)
(unlock-mutex serialization-mutex)))
(unlock-mutex admin-mutex)))))
(define-macro (serialize . forms)
`(call-with-serialization (lambda () ,@forms)))
(define (call-with-parallelization thunk)
(let ((outer-owner #f))
(dynamic-wind
(lambda ()
(lock-mutex admin-mutex)
(set! outer-owner owner)
(if (eqv? outer-owner (dynamic-root))
(begin
(set! owner #f)
(unlock-mutex serialization-mutex)))
(unlock-mutex admin-mutex))
thunk
(lambda ()
(lock-mutex admin-mutex)
(if (eqv? outer-owner (dynamic-root))
(begin
(unlock-mutex admin-mutex)
(lock-mutex serialization-mutex)
(set! owner outer-owner))
(unlock-mutex admin-mutex))))))
(define-macro (parallelize . forms)
`(call-with-parallelization (lambda () ,@forms)))
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