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: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NMatt 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.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Move out the x86-specific tests into tools/perf/arch/x86/tests and
define an 'arch_tests' array, which is the list of tests that only apply
to the build architecture.

We can also now begin to get rid of some of the #ifdef code that is
present in the generic perf tests.
Signed-off-by: NMatt 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: Peter Zijlstra <peterz@infradead.org>
Cc: Vikas Shivappa <vikas.shivappa@intel.com>
Cc: Vince Weaver <vince@deater.net>
Link: http://lkml.kernel.org/n/tip-9s68h4ptg06ah0lgnjz55mqn@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Tests that only make sense for some architectures currently live in
the same place as the generic tests. Move out the x86-specific tests
into tools/perf/arch/x86/tests and define an 'arch_tests' array, which
is the list of tests that only apply to the build architecture.

The main idea is to encourage developers to add arch tests to build
out perf's test coverage, without dumping everything in
tools/perf/tests.
Signed-off-by: NMatt 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: Peter Zijlstra <peterz@infradead.org>
Cc: Vikas Shivappa <vikas.shivappa@intel.com>
Cc: Vince Weaver <vince@deater.net>
Link: http://lkml.kernel.org/n/tip-p4uc1c15ssbj8xj7ku5slpa6@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>