wtf/ParallelJobsOpenMP.h

   1 /*
   2  * Copyright (C) 2011 University of Szeged
   3  * Copyright (C) 2011 Gabor Loki <loki@webkit.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   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.
  14  *
  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.
  26  */
  27
  28 #ifndef ParallelJobsOpenMP_h
  29 #define ParallelJobsOpenMP_h
  30
  31 #if ENABLE(THREADING_OPENMP)
  32
  33 #include <omp.h>
  34
  35 namespace WTF {
  36
  37 class ParallelEnvironment {
  38     WTF_MAKE_NONCOPYABLE(ParallelEnvironment);
  39 public:
  40     typedef void (*ThreadFunction)(void*);
  41
  42     ParallelEnvironment(ThreadFunction threadFunction, size_t sizeOfParameter, int requestedJobNumber) :
  43         m_threadFunction(threadFunction),
  44         m_sizeOfParameter(sizeOfParameter)
  45     {
  46         int maxNumberOfThreads = omp_get_max_threads();
  47
  48         if (!requestedJobNumber || requestedJobNumber > maxNumberOfThreads)
  49             requestedJobNumber = maxNumberOfThreads;
  50
  51         ASSERT(requestedJobNumber > 0);
  52
  53         m_numberOfJobs = requestedJobNumber;
  54
  55     }
  56
  57     int numberOfJobs()
  58     {
  59         return m_numberOfJobs;
  60     }
  61
  62     void execute(unsigned char* parameters)
  63     {
  64         omp_set_num_threads(m_numberOfJobs);
  65
  66 #pragma omp parallel for
  67         for (int i = 0; i < m_numberOfJobs; ++i)
  68             (*m_threadFunction)(parameters + i * m_sizeOfParameter);
  69     }
  70
  71 private:
  72     ThreadFunction m_threadFunction;
  73     size_t m_sizeOfParameter;
  74     int m_numberOfJobs;
  75 };
  76
  77 } // namespace WTF
  78
  79 #endif // ENABLE(THREADING_OPENMP)
  80
  81 #endif // ParallelJobsOpenMP_h