Messages in this thread | | | Date | Tue, 21 Jul 2020 21:18:11 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH V6 11/14] perf/x86/intel: Disable sample-read the slots and metrics events |
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On Tue, Jul 21, 2020 at 12:07:29PM -0400, Liang, Kan wrote:
> I'm trying to produce the bug mentioned above, but I'm not sure under what > situation, the core code will 'promote' the sibling metric events?
Create an event group:
fd = sys_perf_event_open(); fd1 = sys_perf_event_open(.group_fd = fd); ...
then kill the group leader:
close(fd);
Then the sibling events: fdN, should get promoted. Ideally try and use fd1 in a read or so after this.
> I tried the suggested code below. It works well for the sample-read case. > Perf tool errors out as expected.
I'm not sure you can create that case with perf-tool, it's a bit of a daft thing to do, so you'll have to write a custom program.
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