Messages in this thread | | | Date | Fri, 07 May 2010 19:24:49 -0700 | From | Corey Ashford <> | Subject | Re: [BUG] perf_event: when events are grouped, the time enabled / running values are incorrect |
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On 05/07/2010 06:56 PM, Corey Ashford wrote: > Hi, > > There appears to be a bug in the kernel related to reading up the time > running and enabled values for events that are in a group. The group > leader's time running and time enable values look correct, but all of > the other group members have a zero value for their time running and > time enabled fields. > > This happens only when remote monitoring a process (perhaps only after > it has terminated)... when self monitoring, the time running/enabled > values come out non-zero, and the values are the same for all of the > counters (as one would expect since they can be enabled/disabled > simultaneously). > > I've attached a test case which you can place in the tools/perf > subdirectory and compile with just: > > gcc -o show_re_bug show_re_bug.c
I forgot to mention that you should run this with some sort of the load program, like
./show_re_bug md5sum `which gdb`
- Corey
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