android将线程绑定在指定CPU
16lz
2022-01-15
linux下可以直接调用pthread_setaffinity_np,将当前线程绑定在具体的cpu上,而android该API被屏蔽了,需要调用sched这个系统API,详情见下面代码:
package nativelibs;public class Affinity { static { System.loadLibrary("Affinity"); } public static native void bindToCpu(int cpu);}
void set_cur_thread_affinity(int mask) { int err, syscallres; pid_t pid = gettid(); syscallres = syscall(__NR_sched_setaffinity, pid, sizeof(mask), &mask); if (syscallres) { err = errno; LOGE("Error in the syscall setaffinity: mask = %d, err=%d",mask,errno); } LOGD("tid = %d has setted affinity success",pid);}
ok,具体的JNI代码如下:
#include #include #include #include #include #include #include #define TAG "Affinity"#define DEBUG 1#ifndef CPU_ZERO#define CPU_SETSIZE 1024#define __NCPUBITS (8 * sizeof (unsigned long))typedef struct{ unsigned long __bits[CPU_SETSIZE / __NCPUBITS];} cpu_set_t;#define CPU_SET(cpu, cpusetp) \ ((cpusetp)->__bits[(cpu)/__NCPUBITS] |= (1UL << ((cpu) % __NCPUBITS)))#define CPU_ZERO(cpusetp) \ memset((cpusetp), 0, sizeof(cpu_set_t))#else#define CPU_SET(cpu,cpustep) ((void)0)#define CPU_ZERO(cpu,cpustep) ((void)0)#endif#ifdef DEBUG#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG,TAG,__VA_ARGS__)#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,TAG,__VA_ARGS__)#else#define LOGD(...) ((void)0)#define LOGE(...) ((void)0)#endifvoid set_cur_thread_affinity(int mask) { int err, syscallres; pid_t pid = gettid(); syscallres = syscall(__NR_sched_setaffinity, pid, sizeof(mask), &mask); if (syscallres) { err = errno; LOGE("Error in the syscall setaffinity: mask = %d, err=%d",mask,errno); } LOGD("tid = %d has setted affinity success",pid);}static int getCores() { return sysconf(_SC_NPROCESSORS_CONF);}JNIEXPORT int JNICALL Java_nativelibs_Affinity_getCores(JNIEnv *env, jclass type) { return getCores();}JNIEXPORT void JNICALL Java_nativelibs_Affinity_bindToCpu(JNIEnv *env, jclass type, jint cpu) { int cores = getCores(); LOGD("get cpu number = %d\n",cores); if (cpu >= cores) { LOGE("your set cpu is beyond the cores,exit..."); return; } cpu_set_t mask; CPU_ZERO(&mask); CPU_SET(cpu,&mask); set_cur_thread_affinity((int)(&mask)); LOGD("set affinity to %d success",cpu);}
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