Messages in this thread | | | From | Vince Weaver <> | Date | Tue, 15 Jul 2014 10:36:33 -0400 (EDT) | Subject | perf: FORMAT_GROUP on attached process stops working in 3.16-rc |
| |
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?
Thanks,
Vince
| |