android将线程绑定在指定CPU

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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