On Wed, Dec 14, 2016 at 12:48:05PM -0500, kan.li...@intel.com wrote:
> From: Kan Liang <kan.li...@intel.com>
>
> If user has zombie process, the perf record -u will error out.
> Here is an example.
> $ ./testd &
> [1] 23796
> $ sudo perf record -e cycles -u kan
> Error:
> The sys_perf_event_open() syscall returned with 3 (No such process) for
> event (cycles).
> /bin/dmesg may provide additional information.
> No CONFIG_PERF_EVENTS=y kernel support configured?
>
> The source code of testd is as below.
> int main() {
>
> if (fork())
> {
> while (1);
> }
> return 0;
> }
>
> Zombie process is dead process. It is meaningless to profile it.
> It's better to ignore it for user profile.
I recently posted different patch for same issue:
http://marc.info/?l=linux-kernel&m=148153895827359&w=2
jirka
