1 /* 2 * Copyright 2018 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "Thread.h" 18 19 #include <sched.h> 20 #include <unistd.h> 21 22 namespace samples { 23 24 int32_t getNumCpus() { 25 static int32_t sNumCpus = []() { 26 pid_t pid = gettid(); 27 cpu_set_t cpuSet; 28 CPU_ZERO(&cpuSet); 29 sched_getaffinity(pid, sizeof(cpuSet), &cpuSet); 30 31 int32_t numCpus = 0; 32 while (CPU_ISSET(numCpus, &cpuSet)) { 33 ++numCpus; 34 } 35 36 return numCpus; 37 }(); 38 39 return sNumCpus; 40 } 41 42 void setAffinity(int32_t cpu) { 43 cpu_set_t cpuSet; 44 CPU_ZERO(&cpuSet); 45 CPU_SET(cpu, &cpuSet); 46 sched_setaffinity(gettid(), sizeof(cpuSet), &cpuSet); 47 } 48 49 void setAffinity(Affinity affinity) { 50 const int32_t numCpus = getNumCpus(); 51 52 cpu_set_t cpuSet; 53 CPU_ZERO(&cpuSet); 54 for (int32_t cpu = 0; cpu < numCpus; ++cpu) { 55 switch (affinity) { 56 case Affinity::None: 57 CPU_SET(cpu, &cpuSet); 58 break; 59 case Affinity::Even: 60 if (cpu % 2 == 0) CPU_SET(cpu, &cpuSet); 61 break; 62 case Affinity::Odd: 63 if (cpu % 2 == 1) CPU_SET(cpu, &cpuSet); 64 break; 65 } 66 } 67 68 sched_setaffinity(gettid(), sizeof(cpuSet), &cpuSet); 69 } 70 71 } // namespace samples { 72
