linux clock()

#include <stdio.h>
#include <time.h>

int main() {
    clock_t start, end;
    double cpu_time_used;

    start = clock();

    // 模拟一些工作
    for (int i = 0; i < 1000000; i++) {
        // 做一些计算
    }

    end = clock();
    cpu_time_used = ((double) (end - start)) / CLOCKS_PER_SEC;

    printf("Time used: %f seconds\n", cpu_time_used);

    return 0;
}

#include <stdio.h>
#include <time.h>

int main() {
    struct timespec start, end;
    double elapsed;

    clock_gettime(CLOCK_MONOTONIC, &start);

    // 模拟一些工作
    for (int i = 0; i < 1000000; i++) {
        // 做一些计算
    }

    clock_gettime(CLOCK_MONOTONIC, &end);
    elapsed = (end.tv_sec - start.tv_sec) + (end.tv_nsec - start.tv_nsec) / 1e9;

    printf("Elapsed time: %f seconds\n", elapsed);

    return 0;
}

#include <stdio.h>
#include <pthread.h>
#include <time.h>

void* thread_func(void* arg) {
    clockid_t clk_id;
    pthread_getcpuclockid(pthread_self(), &clk_id);

    struct timespec start, end;
    clock_gettime(clk_id, &start);

    // 模拟一些工作
    for (int i = 0; i < 1000000; i++) {
        // 做一些计算
    }

    clock_gettime(clk_id, &end);
    double elapsed = (end.tv_sec - start.tv_sec) + (end.tv_nsec - start.tv_nsec) / 1e9;

    printf("Thread time: %f seconds\n", elapsed);

    return NULL;
}

int main() {
    pthread_t thread;
    pthread_create(&thread, NULL, thread_func, NULL);
    pthread_join(thread, NULL);

    return 0;
}