I've read the post before, and I've seen a lot of saying "sched_child_runs_first just not a guarantee of anything". But still, there should be a moment that child process ran first. From my experiment, there was no single time that child process ran before father process. Isn't it interesting ? On Fri, Dec 8, 2017 at 7:18 PM, YU Bo <tsu.yubo@gmail.com> wrote:
Hi,
On Fri, Dec 08, 2017 at 11:07:15AM +0800, Rock Lee wrote:
Hi,
I ran my test code but always got the father process run first, even after setting sched_child_runs_first. Could anyone give me a hint? Here is my test code.
#include <stdio.h> #include <unistd.h> #include <sys/time.h>
int main(void) { struct timeval tv; struct timezone tz; int err; pid_t ret = fork();
if (ret == 0) { err = gettimeofday(&tv, &tz); if (!err) printf("child time sec %d, usec %d\n", tv.tv_sec, tv.tv_usec);
printf("this child.\n"); } else if (ret > 1) { err = gettimeofday(&tv, &tz);
if (!err) printf("father time sec %d, usec %d\n", tv.tv_sec, tv.tv_usec); printf("this father.\n"); } else printf("err!!\n"); return 0; }
Maybe here:
https://stackoverflow.com/questions/17391201/does-proc-sys-kernel-sched-chil...
Bo
-- Cheers, Rock
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-- Cheers, Rock