perf: regression with PERF_EVENT_IOC_REFRESH
From: Vince Weaver
Date: Mon May 23 2011 - 16:05:12 EST
the changeset 2e939d1d perf: Limit event refresh to sampling event
changes the behavior of
ioctl( , PERF_EVENT_IOC_REFRESH, )
before the changeset, you could have a counter group where only one of the
subevents was sampling. PERF_EVENT_IOC_REFRESH would correctly enable
sampling for only that subevent.
With the changeset applied, this fails with EINVALID. Now you can only
sample in a group leader.
Was this an intended change? It breaks various of our PAPI regression
tests that worked fine before the change was committed.
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