lkml.org 
[lkml]   [2014]   [Jul]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: perf: FORMAT_GROUP on attached process stops working in 3.16-rc
On Tue, Jul 15, 2014 at 10:36:33AM -0400, Vince Weaver wrote:
> Hello
>
> I noticed in the 3.16-rc kernels that one of my regression tests was
> failing, specifically
> https://github.com/deater/perf_event_tests/blob/master/tests/bugs/read_group_attached.c
>
> This test creates an event group with two events and PERF_FORMAT_GROUP
> set.
>
> It creates a child process, stops it, attaches the event group to it,
> starts the events and the child, waits for the child to finish, stops the
> events, then reads the value.
>
> In theory a subsequent read from the group leader should return values for
> *both* events (due to PERF_FORMAT_GROUP) but this stopped working, it only
> returns the value for the leader.
>
> I've bisected it down to change: 15a2d4de0eab5
> "perf: Always destroy groups on exit"
>
> So is this expected behavior due to this patch, or is it a regression?

Regression, lemme try and wrap my head around it. Thanks!
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2014-07-15 17:21    [W:0.068 / U:0.300 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site