多线程写日志时，输出的线程id不是子线程的id
ahchengrui opened this issue · comments
修改linux demo为多线程模式，verbose里面的tid不是子线程本身的id？
I/elog [12-25 18:28:36] EasyLogger V2.0.3 is initialize success.
do multithread test...
start create thread........
start create thread........
id=0
tid =3152430848
id=1
tid =3144038144
elog_output----tid:13995
A/main [12-25 18:28:36 pid:31856 tid:13995] (main.c test_elog:86)Hello EasyLogger! 0
E/main [12-25 18:28:36] Hello EasyLogger! 0
W/main [12-25 18:28:36] Hello EasyLogger! 0
I/main [12-25 18:28:36] Hello EasyLogger! 0
elog_output----tid:13995
elog_output----tid:13995
elog_output----tid:13995
A/main [12-25 18:28:36 pid:31856 tid:13995] (main.c test_elog:86)Hello EasyLogger! 1
E/main [12-25 18:28:36] Hello EasyLogger! 1
W/main [12-25 18:28:36] Hello EasyLogger! 1
I/main [12-25 18:28:36] Hello EasyLogger! 1
elog_output----tid:13995
elog_output----tid:13995
D/main [12-25 18:28:36 pid:31856 tid:13995] (main.c:90)Hello EasyLogger! 0
V/main [12-25 18:28:36 pid:31856 tid:13995] (main.c:91)Hello EasyLogger! 0
D/main [12-25 18:28:36 pid:31856 tid:13995] (main.c:90)Hello EasyLogger! 1
V/main [12-25 18:28:36 pid:31856 tid:13995] (main.c:91)Hello EasyLogger! 1
咦~~你看下你的 tid 跟自带 demo 获取 tid 的方式一样吗？
EasyLogger/demo/os/linux/easylogger/port/elog_port.c
Lines 110 to 121 in f4af95b
demo/os/linux/main.c 代码修改如下
` /* start EasyLogger */
elog_start();
/* test logger output */
_test_multithread();
return EXIT_SUCCESS;
}
static void _test_multithread()
{
pthread_t ptt[2];
int i;
for (i = 0; i < 2; ++i) {
printf("start create thread........\n");
pthread_create(&ptt[i], NULL, test_elog, i);
}
for (i = 0; i < 2; ++i) {
pthread_join(ptt[i], NULL);
}
}
void test_elog(void *arg) {
int id = (int )arg;
static char cur_thread_info[10] = { 0 };
snprintf(cur_thread_info, 10, "tid:%04ld", pthread_self());
printf("pthread id is %s\n",cur_thread_info);
while(true) {
/ test log output for all level */
log_a("Hello EasyLogger! %d", id);
log_e("Hello EasyLogger! %d", id);
log_w("Hello EasyLogger! %d", id);
log_i("Hello EasyLogger! %d", id);
log_d("Hello EasyLogger! %d", id);
log_v("Hello EasyLogger! %d", id);
// elog_raw("Hello EasyLogger!");
sleep(5);
}
}
`
运行结果如下：
I/elog [12-25 21:44:15] EasyLogger V2.0.3 is initialize success.
start create thread........
start create thread........
pthread id is tid:20511
pthread id is tid:20427
elog_output----tid:14062
A/main [12-25 21:44:15 pid:23758 tid:14062] (main.c test_elog:81)Hello EasyLogger! 0
E/main [12-25 21:44:15] Hello EasyLogger! 0
W/main [12-25 21:44:15] Hello EasyLogger! 0
I/main [12-25 21:44:15] Hello EasyLogger! 0
elog_output----tid:14062
elog_output----tid:14062
D/main [12-25 21:44:15 pid:23758 tid:14062] (main.c:85)Hello EasyLogger! 0
V/main [12-25 21:44:15 pid:23758 tid:14062] (main.c:86)Hello EasyLogger! 0
elog_output----tid:14062
A/main [12-25 21:44:15 pid:23758 tid:14062] (main.c test_elog:81)Hello EasyLogger! 1
E/main [12-25 21:44:15] Hello EasyLogger! 1
W/main [12-25 21:44:15] Hello EasyLogger! 1
I/main [12-25 21:44:15] Hello EasyLogger! 1
elog_output----tid:14062
elog_output----tid:14062
D/main [12-25 21:44:15 pid:23758 tid:14062] (main.c:85)Hello EasyLogger! 1
V/main [12-25 21:44:15 pid:23758 tid:14062] (main.c:86)Hello EasyLogger! 1
获取到的线程id与V/main里面打印的线程id不一致
pthread 我现在用的不多，能深入查下原因吗？
线程号不一致的问题，估计是默认使用的异步输出，所以打印的线程号是异步线程的id。
应该不是，日志帧内容在转到异步输出前，就已经定好了
我才看了下代码，发现了问题，是因为snprintf(cur_thread_info, 10, "tid:%ld", pthread_self());这行代码导致的。
1、组包用的是%ld，和%d的输出不一样。
2、id长度很大，组包的时候有截断，无法输出全部id号。
@tianlongqin 分析的有道理 👍
- snprintf(cur_thread_info, 10, "tid:%04ld", pthread_self()); ld要修改成lu才能正常打印出pthread_self()的返回值
- pthread_self()的返回线程ID非top -H显示的线程ID,建议将pthread_self()更换成syscall的方式