source/common/wavefront.cpp

   1 /*****************************************************************************
   2  * Copyright (C) 2013 x265 project
   3  *
   4  * Authors: Steve Borho <steve@borho.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111, USA.
  19  *
  20  * This program is also available under a commercial proprietary license.
  21  * For more information, contact us at license @ x265.com
  22  *****************************************************************************/
  23
  24 #include "threadpool.h"
  25 #include "threading.h"
  26 #include "wavefront.h"
  27 #include "common.h"
  28
  29 namespace x265 {
  30 // x265 private namespace
  31
  32 bool WaveFront::init(int numRows)
  33 {
  34     m_numRows = numRows;
  35
  36     m_numWords = (numRows + 31) >> 5;
  37     m_internalDependencyBitmap = X265_MALLOC(uint32_t, m_numWords);
  38     if (m_internalDependencyBitmap)
  39         memset((void*)m_internalDependencyBitmap, 0, sizeof(uint32_t) * m_numWords);
  40
  41     m_externalDependencyBitmap = X265_MALLOC(uint32_t, m_numWords);
  42     if (m_externalDependencyBitmap)
  43         memset((void*)m_externalDependencyBitmap, 0, sizeof(uint32_t) * m_numWords);
  44
  45     return m_internalDependencyBitmap && m_externalDependencyBitmap;
  46 }
  47
  48 WaveFront::~WaveFront()
  49 {
  50     x265_free((void*)m_internalDependencyBitmap);
  51     x265_free((void*)m_externalDependencyBitmap);
  52 }
  53
  54 void WaveFront::clearEnabledRowMask()
  55 {
  56     memset((void*)m_externalDependencyBitmap, 0, sizeof(uint32_t) * m_numWords);
  57 }
  58
  59 void WaveFront::enqueueRow(int row)
  60 {
  61     uint32_t bit = 1 << (row & 31);
  62     ATOMIC_OR(&m_internalDependencyBitmap[row >> 5], bit);
  63     if (m_pool) m_pool->pokeIdleThread();
  64 }
  65
  66 void WaveFront::enableRow(int row)
  67 {
  68     uint32_t bit = 1 << (row & 31);
  69     ATOMIC_OR(&m_externalDependencyBitmap[row >> 5], bit);
  70 }
  71
  72 void WaveFront::enableAllRows()
  73 {
  74     memset((void*)m_externalDependencyBitmap, ~0, sizeof(uint32_t) * m_numWords);
  75 }
  76
  77 bool WaveFront::dequeueRow(int row)
  78 {
  79     uint32_t bit = 1 << (row & 31);
  80     return !!(ATOMIC_AND(&m_internalDependencyBitmap[row >> 5], ~bit) & bit);
  81 }
  82
  83 bool WaveFront::findJob(int threadId)
  84 {
  85     unsigned long id;
  86
  87     // thread safe
  88     for (int w = 0; w < m_numWords; w++)
  89     {
  90         uint32_t oldval = m_internalDependencyBitmap[w] & m_externalDependencyBitmap[w];
  91         while (oldval)
  92         {
  93             CTZ(id, oldval);
  94
  95             uint32_t bit = 1 << id;
  96             if (ATOMIC_AND(&m_internalDependencyBitmap[w], ~bit) & bit)
  97             {
  98                 /* we cleared the bit, we get to process the row */
  99                 processRow(w * 32 + id, threadId);
 100                 return true;
 101             }
 102
 103             // some other thread cleared the bit, try another bit
 104             oldval = m_internalDependencyBitmap[w] & m_externalDependencyBitmap[w];
 105         }
 106     }
 107
 108     // made it through the bitmap without finding any enqueued rows
 109     return false;
 110 }
 111 }