Semaphore是一种用于进程同步和互斥的机制,而在ARM8上主要存在两种Semaphore,分别是System V Semaphore和Posix Semaphore。下面介绍一种针对ARM8上Semaphore性能比较的解决方法。
方法步骤如下:
首先,需要在ARM8上安装一些性能测试工具,如sysbench等。
接下来,需要编写一些测试代码,来比较System V Semaphore和Posix Semaphore的性能。
以System V Semaphore为例:
#include
#include
#include
#include
#include
#include
#define SEM_KEY 1234
#define SEM_NUM 1
int main(int argc, char **argv)
{
key_t key = SEM_KEY;
int semid, i, nloop = 1000000;
struct sembuf wait_1 = {0, -1, SEM_UNDO};
struct sembuf signal_1 = {0, 1, SEM_UNDO};
struct timeval start, end;
if((semid = semget(key, SEM_NUM, IPC_CREAT|0666)) == -1)
{
perror("semget error");
exit(EXIT_FAILURE);
}
semctl(semid, 0, SETVAL, 1);
if(gettimeofday(&start, NULL) == -1)
{
perror("gettimeofday error");
exit(EXIT_FAILURE);
}
for (i = 0; i < nloop; i++)
{
semop(semid, &wait_1, 1);
semop(semid, &signal_1, 1);
}
if(gettimeofday(&end, NULL) == -1)
{
perror("gettimeofday error");
exit(EXIT_FAILURE);
}
printf("System V Semaphore: %ld microseconds\n", ((end.tv_sec*1000000 + end.tv_usec) - (start.tv_sec*1000000 + start.tv_usec)));
exit(EXIT_SUCCESS);
}
``