michael@0: /*
michael@0:  * Copyright 2012 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #ifndef _GNU_SOURCE
michael@0: #define _GNU_SOURCE //for pthread_setaffinity_np
michael@0: #endif
michael@0: 
michael@0: #include "SkThreadUtils.h"
michael@0: #include "SkThreadUtils_pthread.h"
michael@0: 
michael@0: #include <pthread.h>
michael@0: 
michael@0: static int nth_set_cpu(unsigned int n, cpu_set_t* cpuSet) {
michael@0:     n %= CPU_COUNT(cpuSet);
michael@0:     for (unsigned int setCpusSeen = 0, currentCpu = 0; true; ++currentCpu) {
michael@0:         if (CPU_ISSET(currentCpu, cpuSet)) {
michael@0:             ++setCpusSeen;
michael@0:             if (setCpusSeen > n) {
michael@0:                 return currentCpu;
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: bool SkThread::setProcessorAffinity(unsigned int processor) {
michael@0:     SkThread_PThreadData* pthreadData = static_cast<SkThread_PThreadData*>(fData);
michael@0:     if (!pthreadData->fValidPThread) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     cpu_set_t parentCpuset;
michael@0:     if (0 != pthread_getaffinity_np(pthread_self(), sizeof(cpu_set_t), &parentCpuset)) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     cpu_set_t cpuset;
michael@0:     CPU_ZERO(&cpuset);
michael@0:     CPU_SET(nth_set_cpu(processor, &parentCpuset), &cpuset);
michael@0:     return 0 == pthread_setaffinity_np(pthreadData->fPThread,
michael@0:                                        sizeof(cpu_set_t),
michael@0:                                        &cpuset);
michael@0: }