附录.md

附录

工具函数

获取mstime

/* Return the UNIX time in microseconds */
long long ustime(void) {
    struct timeval tv;
    long long ust;

    gettimeofday(&tv, NULL);
    ust = ((long long)tv.tv_sec)*1000000;
    ust += tv.tv_usec;
    return ust;
}

/* Return the UNIX time in milliseconds */
mstime_t mstime(void) {
    return ustime()/1000;
}

linux automic

#define atomicIncr(var,count) __sync_add_and_fetch(&var,(count))
#define atomicGetIncr(var,oldvalue_var,count) do { \
    oldvalue_var = __sync_fetch_and_add(&var,(count)); \
} while(0)
#define atomicDecr(var,count) __sync_sub_and_fetch(&var,(count))
#define atomicGet(var,dstvar) do { \
    dstvar = __sync_sub_and_fetch(&var,0); \
} while(0)
#define atomicSet(var,value) do { \
    while(!__sync_bool_compare_and_swap(&var,var,value)); \
} while(0)
/* Actually the builtin issues a full memory barrier by default. */
#define atomicGetWithSync(var,dstvar) { \
    dstvar = __sync_sub_and_fetch(&var,0,__sync_synchronize); \
    ANNOTATE_HAPPENS_AFTER(&var); \
} while(0)
#define atomicSetWithSync(var,value) do { \
    ANNOTATE_HAPPENS_BEFORE(&var);  \
    while(!__sync_bool_compare_and_swap(&var,var,value,__sync_synchronize)); \
} while(0)