Re: [PATCH v3 6/7] perf test: Improve pmu event metric testing

[Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>]

Em Tue, May 19, 2020 at 01:15:41PM -0700, Ian Rogers escreveu:
> On Tue, May 19, 2020 at 12:06 PM Arnaldo Carvalho de Melo
> <arnaldo.melo@gmail.com> wrote:
> >
> > Em Fri, May 15, 2020 at 03:17:31PM -0700, Ian Rogers escreveu:
> > > Break pmu-events test into 2 and add a test to verify that all pmu
> > > metric expressions simply parse. Try to parse all metric ids/events,
> > > skip/warn if metrics for the current architecture fail to parse. To
> > > support warning for a skip, and an ability for a subtest to describe why
> > > it skips.
> > >
> > > Tested on power9, skylakex, haswell, broadwell, westmere, sandybridge and
> > > ivybridge.
> > >
> > > May skip/warn on other architectures if metrics are invalid. In
> > > particular s390 is untested, but its expressions are trivial. The
> > > untested architectures with expressions are power8, cascadelakex,
> > > tremontx, skylake, jaketown, ivytown and variants of haswell and
> > > broadwell.
> > >
> > > v3. addresses review comments from John Garry <john.garry@huawei.com>,
> > > Jiri Olsa <jolsa@redhat.com> and Arnaldo Carvalho de Melo
> > > <acme@kernel.org>.
> > > v2. changes the commit message as event parsing errors no longer cause
> > > the test to fail.
> > >
> > > Signed-off-by: Ian Rogers <irogers@google.com>
> > > Cc: Adrian Hunter <adrian.hunter@intel.com>
> > > Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> > > Cc: Andi Kleen <ak@linux.intel.com>
> > > Cc: Jin Yao <yao.jin@linux.intel.com>
> > > Cc: Jiri Olsa <jolsa@redhat.com>
> > > Cc: John Garry <john.garry@huawei.com>
> > > Cc: Kajol Jain <kjain@linux.ibm.com>
> > > Cc: Kan Liang <kan.liang@linux.intel.com>
> > > Cc: Leo Yan <leo.yan@linaro.org>
> > > Cc: Mark Rutland <mark.rutland@arm.com>
> > > Cc: Namhyung Kim <namhyung@kernel.org>
> > > Cc: Paul Clarke <pc@us.ibm.com>
> > > Cc: Peter Zijlstra <peterz@infradead.org>
> > > Cc: Stephane Eranian <eranian@google.com>
> > > Link: http://lore.kernel.org/lkml/20200513212933.41273-1-irogers@google.com
> > > [ split from a larger patch ]
> > > Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> > > ---
> > >  tools/perf/tests/builtin-test.c |   7 ++
> > >  tools/perf/tests/pmu-events.c   | 168 ++++++++++++++++++++++++++++++--
> > >  tools/perf/tests/tests.h        |   3 +
> > >  3 files changed, 172 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
> > > index baee735e6aa5..9553f8061772 100644
> > > --- a/tools/perf/tests/builtin-test.c
> > > +++ b/tools/perf/tests/builtin-test.c
> > > @@ -75,6 +75,13 @@ static struct test generic_tests[] = {
> > >       {
> > >               .desc = "PMU events",
> > >               .func = test__pmu_events,
> > > +             .subtest = {
> > > +                     .skip_if_fail   = false,
> > > +                     .get_nr         = test__pmu_events_subtest_get_nr,
> > > +                     .get_desc       = test__pmu_events_subtest_get_desc,
> > > +                     .skip_reason    = test__pmu_events_subtest_skip_reason,
> > > +             },
> > > +
> > >       },
> > >       {
> > >               .desc = "DSO data read",
> > > diff --git a/tools/perf/tests/pmu-events.c b/tools/perf/tests/pmu-events.c
> > > index d64261da8bf7..e21f0addcfbb 100644
> > > --- a/tools/perf/tests/pmu-events.c
> > > +++ b/tools/perf/tests/pmu-events.c
> > > @@ -8,6 +8,9 @@
> > >  #include <linux/zalloc.h>
> > >  #include "debug.h"
> > >  #include "../pmu-events/pmu-events.h"
> > > +#include "util/evlist.h"
> > > +#include "util/expr.h"
> > > +#include "util/parse-events.h"
> > >
> > >  struct perf_pmu_test_event {
> > >       struct pmu_event event;
> > > @@ -144,7 +147,7 @@ static struct pmu_events_map *__test_pmu_get_events_map(void)
> > >  }
> > >
> > >  /* Verify generated events from pmu-events.c is as expected */
> > > -static int __test_pmu_event_table(void)
> > > +static int test_pmu_event_table(void)
> > >  {
> > >       struct pmu_events_map *map = __test_pmu_get_events_map();
> > >       struct pmu_event *table;
> > > @@ -347,14 +350,11 @@ static int __test__pmu_event_aliases(char *pmu_name, int *count)
> > >       return res;
> > >  }
> > >
> > > -int test__pmu_events(struct test *test __maybe_unused,
> > > -                  int subtest __maybe_unused)
> > > +
> > > +static int test_aliases(void)
> > >  {
> > >       struct perf_pmu *pmu = NULL;
> > >
> > > -     if (__test_pmu_event_table())
> > > -             return -1;
> > > -
> > >       while ((pmu = perf_pmu__scan(pmu)) != NULL) {
> > >               int count = 0;
> > >
> > > @@ -377,3 +377,159 @@ int test__pmu_events(struct test *test __maybe_unused,
> > >
> > >       return 0;
> > >  }
> > > +
> > > +static bool is_number(const char *str)
> > > +{
> > > +     char *end_ptr;
> > > +
> > > +     strtod(str, &end_ptr);
> > > +     return end_ptr != str;
> > > +}
> >
> > So, this breaks in some systems:
> >
> > cc1: warnings being treated as errors
> > tests/pmu-events.c: In function 'is_number':
> > tests/pmu-events.c:385: error: ignoring return value of 'strtod', declared with attribute warn_unused_result
> > mv: cannot stat `/tmp/build/perf/tests/.pmu-events.o.tmp': No such file or director
> >
> > So I'm changing it to verify the result of strtod() which is, humm,
> > interesting, please check:
> 
> Thanks Arnaldo and sorry for the difficulty. This looks like a good fix.
> 
> > diff --git a/tools/perf/tests/pmu-events.c b/tools/perf/tests/pmu-events.c
> > index 3de59564deb0..6c58c3a89e6b 100644
> > --- a/tools/perf/tests/pmu-events.c
> > +++ b/tools/perf/tests/pmu-events.c
> > @@ -1,4 +1,5 @@
> >  // SPDX-License-Identifier: GPL-2.0
> > +#include "math.h"
> >  #include "parse-events.h"
> >  #include "pmu.h"
> >  #include "tests.h"
> > @@ -381,8 +382,12 @@ static int test_aliases(void)
> >  static bool is_number(const char *str)
> >  {
> >         char *end_ptr;
> > +       double v;
> >
> > -       strtod(str, &end_ptr);
> > +       errno = 0;
> > +       v = strtod(str, &end_ptr);
> > +       if ((errno == ERANGE && (v == HUGE_VAL || v == -HUGE_VAL)) || (errno != 0 && v == 0.0))
> 
> errno can either be 0 or ERANGE here, but we test both. Perhaps use
> errno != 0 for both cases as the man page notes suggest doing this.
> The tests using v are necessary to avoid the unused result, but
> presumably any errno case should return false here? I guess testing
> that is redundant as the return below will catch it. Perhaps this
> should be:
> 
> errno = 0;
> v = strtod(str, &end_ptr);
> (void)v;  /* We don't care for the value of the double, just that it
> converts. Avoid unused result warnings. */
> return errno == 0 && end_ptr != str;

Ok, I'll try that one.

- Arnaldo
 
> Thanks,
> Ian
> 
> > +               return false;
> >         return end_ptr != str;
> >  }
> >

-- 

- Arnaldo