2 * Copyright (C) 2011 University of Szeged
3 * Copyright (C) 2011 Gabor Loki <loki@webkit.org>
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY UNIVERSITY OF SZEGED ``AS IS'' AND ANY
16 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL UNIVERSITY OF SZEGED OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
22 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
23 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 #ifndef ParallelJobsGeneric_h
29 #define ParallelJobsGeneric_h
31 #if ENABLE(THREADING_GENERIC)
33 #include <wtf/RefCounted.h>
34 #include <wtf/Threading.h>
38 static const unsigned int maxParallelThreads = 2;
40 class ParallelEnvironment {
41 WTF_MAKE_FAST_ALLOCATED;
43 typedef void (*ThreadFunction)(void*);
45 ParallelEnvironment(ThreadFunction threadFunction, size_t sizeOfParameter, unsigned int requestedJobNumber) :
46 m_threadFunction(threadFunction),
47 m_sizeOfParameter(sizeOfParameter)
49 if (!requestedJobNumber || requestedJobNumber > maxParallelThreads)
50 requestedJobNumber = maxParallelThreads;
53 s_threadPool = new Vector< RefPtr<ThreadPrivate> >();
55 // The main thread should be also a worker.
56 unsigned int maxNewThreads = requestedJobNumber - 1;
58 for (unsigned int i = 0; i < maxParallelThreads && m_threads.size() < maxNewThreads; ++i) {
59 if (s_threadPool->size() < i + 1)
60 s_threadPool->append(ThreadPrivate::create());
62 if ((*s_threadPool)[i]->tryLockFor(this))
63 m_threads.append((*s_threadPool)[i]);
66 m_numberOfJobs = m_threads.size() + 1;
71 return m_numberOfJobs;
74 void execute(unsigned char* parameters)
77 for (i = 0; i < m_threads.size(); ++i) {
78 m_threads[i]->execute(m_threadFunction, parameters);
79 parameters += m_sizeOfParameter;
82 // The work for the main thread
83 (*m_threadFunction)(parameters);
85 // Wait until all jobs are done.
86 for (i = 0; i < m_threads.size(); ++i)
87 m_threads[i]->waitForFinish();
90 class ThreadPrivate : public RefCounted<ThreadPrivate> {
99 bool tryLockFor(ParallelEnvironment*);
101 void execute(ThreadFunction, void*);
103 void waitForFinish();
105 static PassRefPtr<ThreadPrivate> create()
107 return adoptRef(new ThreadPrivate());
110 static void* workerThread(void*);
113 ThreadIdentifier m_threadID;
115 ParallelEnvironment* m_parent;
117 mutable Mutex m_mutex;
118 ThreadCondition m_threadCondition;
120 ThreadFunction m_threadFunction;
125 ThreadFunction m_threadFunction;
126 size_t m_sizeOfParameter;
129 Vector< RefPtr<ThreadPrivate> > m_threads;
130 static Vector< RefPtr<ThreadPrivate> >* s_threadPool;
135 #endif // ENABLE(THREADING_GENERIC)
138 #endif // ParallelJobsGeneric_h