Re: Perf tests for hw events

[Arnaldo Carvalho de Melo]

Em Thu, Jan 22, 2015 at 12:40:14PM +0000, Matt Fleming escreveu:
> Folks,
> 
> In the process of writing perf support for Intel's Cache QoS Monitoring
> feature [0] I've had to write my own userland tests to drive tools/perf
> and indirectly the kernel internals. I'm now getting requests for these
> tests from various people and it occurs to me that they should probably
> live in the kernel tree.
> 
> The tests I've got do a couple of things like setting up a perf_event
> cgroup and assigning enough tasks to trigger the RMID recycling code in
> the CQM driver, ensuring that we can run multiple events simultaneously
> (that the event scheduling/rotation code works), etc.
> 
> Does anything like this already exist for hw events? I couldn't find
> anything specific to hw events from snooping around in tools/perf/tests. 
> 
> I propose we add some hw event tests to the kernel tree. These will
> provide,
> 
>  - regression tests
>  - a source of documentation for how to use the events

That is the description for tools/perf/tests/ please send your patches
for adding new entries there.

> We should only test those hw events that are present on a user's
> machine; there's no sense in emulating things.

At some point 'perf test' should grow infrastructure to specify what is
required for a test so that it auto-skips those, possibly not even
bothering the user telling something can't be tested. Right now for
things like tests that requires finding a vmlinux, if it doesn't find
it, it will just print "Skipped", etc.
 
> Thoughts?
> 
> [0] - https://lkml.kernel.org/r/1415999712-5850-1-git-send-email-matt@xxxxxxxxxxxxxxxxx

- Arnaldo
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