Messages in this thread | | | Date | Sat, 6 Aug 2011 13:10:10 -0700 | Subject | Re: [PATCH v2 6/6] perf tool: Parse general/raw events from sysfs | From | Stephane Eranian <> |
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Hi,
On Fri, Jul 15, 2011 at 7:35 AM, Lin Ming <ming.m.lin@intel.com> wrote: > PMU can export general events to sysfs, for example, > > /sys/bus/event_source/devices/uncore/events > └── cycle > > Then specify the event as <pmu>:<event>, > > $ sudo perf stat -a -C 0 -e uncore:cycle
I think this event syntax should be adjusted a bit.
How would the tool differentiate: perf stat -e uncore:cycle form: perf stat -e cycle:u
It would have to scan sysfs for a 'cycle' PMU and conclude there is none, then resolve the 'cycle' event name. And if you're unlucky and you have a event name that matches the PMU name, you get into troubles.
I think, one could instead do:
perf stat -e uncore::cycle:k
That way, by virtue of the '::' separator, the tool would know that it needs to first look into sysfs for an 'uncore' PMU, then it needs to look for the 'cycle' event.
I also use the '::' notation in libpfm4 to separate the PMU model form the event+umask+modifiers.
I also suspect that with this sysfs interface for PMU models, you would simply add a number to differentiate each instance of a PMU. So for GPU, you would do: perf stat -e gfx0::cycles
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