perf tests: Add Intel CQM test
authorMatt Fleming <matt.fleming@intel.com>
Mon, 5 Oct 2015 14:40:21 +0000 (15:40 +0100)
committerArnaldo Carvalho de Melo <acme@redhat.com>
Mon, 5 Oct 2015 19:56:07 +0000 (16:56 -0300)
commit035827e9f2bd71a280f4eb58c65811d377ab2217
treefd989e82be49f2363d7c9b5dc0e4ddb86fbe4eaa
parentd8b167f9d8af817073ee35cf904e2e527465dbc1
perf tests: Add Intel CQM test

Peter reports that it's possible to trigger a WARN_ON_ONCE() in the
Intel CQM code by combining a hardware event and an Intel CQM
(software) event into a group. Unfortunately, the perf tools are not
able to create this bundle and we need to manually construct a test
case.

For posterity, record Peter's proof of concept test case in tools/perf
so that it presents a model for how we can perform architecture
specific tests, or "arch tests", in perf in the future.

The particular issue triggered in the test case is that when the
counter for the hardware event overflows and triggers a PMI we'll read
both the hardware event and the software event counters.
Unfortunately, for CQM that involves performing an IPI to read the CQM
event counters on all sockets, which in NMI context triggers the
WARN_ON_ONCE().

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kanaka Juvva <kanaka.d.juvva@intel.com>
Cc: Vikas Shivappa <vikas.shivappa@intel.com>
Cc: Vince Weaver <vince@deater.net>
Link: http://lkml.kernel.org/r/1437490509-15373-1-git-send-email-matt@codeblueprint.co.uk
Link: http://lkml.kernel.org/n/tip-3p4ra0u8vzm7m289a1m799kf@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
tools/perf/arch/x86/include/arch-tests.h
tools/perf/arch/x86/tests/Build
tools/perf/arch/x86/tests/arch-tests.c
tools/perf/arch/x86/tests/intel-cqm.c [new file with mode: 0644]