Messages in this thread Patch in this message | | | From | Namhyung Kim <> | Date | Tue, 9 Apr 2024 16:17:28 -0700 | Subject | Re: [PATCH 3/3] perf tests: Skip "test data symbol" on Neoverse N1 |
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Hi Ian and James,
On Tue, Apr 9, 2024 at 8:39 AM Ian Rogers <irogers@google.com> wrote: > > On Tue, Apr 9, 2024 at 1:48 AM James Clark <james.clark@arm.com> wrote: > > > > To prevent anyone from seeing a test failure appear as a regression and > > thinking that it was caused by their code change, just skip the test on > > N1. > > > > It can be caused by any unrelated change that shifts the loop into an > > unfortunate position in the Perf binary which is almost impossible to > > debug as the root cause of the test failure. Ultimately it's caused by > > the referenced errata. > > > > Fixes: 60abedb8aa90 ("perf test: Introduce script for data symbol testing") > > Signed-off-by: James Clark <james.clark@arm.com> > > This change makes me sad :-( Is there no hope of aligning the loop? We > have little enough testing coverage for memory events and even precise > events on ARM that anything take away testing coverage feels like we > should try to do better.
Can we just add some noise in the loop?
Thanks, Namhyung
diff --git a/tools/perf/tests/workloads/datasym.c b/tools/perf/tests/workloads/datasym.c index ddd40bc63448..e2514bf393cd 100644 --- a/tools/perf/tests/workloads/datasym.c +++ b/tools/perf/tests/workloads/datasym.c @@ -16,6 +16,8 @@ static int datasym(int argc __maybe_unused, const char **argv __maybe_unused) { for (;;) { buf1.data1++; + if ((buf1.data1 % 100129) == 0) + buf1.data1++; buf1.data2 += buf1.data1; } return 0;
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