Messages in this thread | | | Date | Tue, 15 Jul 2014 16:37:45 +0200 | From | Peter Zijlstra <> | Subject | Re: perf: FORMAT_GROUP on attached process stops working in 3.16-rc |
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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] | |