Messages in this thread | | | Date | Thu, 8 Oct 2009 16:12:33 +0200 | Subject | perf_events: issue with scaling information | From | stephane eranian <> |
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Hi,
With libpfm4, I have developed a set of examples which are using perf_events to demonstrate typical counting and sampling scenarios.
In two of the sampling program, it appears time_enabled, time_running included in the samples are incorrect.
The program notify_self.c uses IOC_REFRESH to get a notification for each sample. The first sample comes out with time_running = time_enabled =0, subsequent samples return non-zero information. I suspect something is wrong initially because of IOC_REFRESH. This is using an event group.
The program task_smpl.c is sampling another process. Although the scaling information is requested, all samples come out with time_running = time_enabled=0. The rest of the sample is correct, so it's not like I am not correctly reading the sample. The program is using an event group.
I suspect both issues may be related.
You can obtain the test programs (which are open-source!), by cloning the GIT tree at: git://perfmon2.git.sourceforge.net/gitroot/perfmon2/libpfm4
Thanks.
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