linux-kernel - Re: [PATCH v4] perf test tsc: Fix error message report when not supported.

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Date:   Sat, 9 Apr 2022 11:43:48 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Adrian Hunter <adrian.hunter@...el.com>
Cc:     Chengdong Li <brytonlee01@...il.com>, linux-kernel@...r.kernel.org,
        linux-perf-users@...r.kernel.org, peterz@...radead.org,
        mingo@...hat.com, mark.rutland@....com,
        alexander.shishkin@...ux.intel.com, jolsa@...hat.com,
        namhyung@...nel.org, ak@...ux.intel.com, likexu@...cent.com,
        chengdongli@...cent.com
Subject: Re: [PATCH v4] perf test tsc: Fix error message report when not
 supported.

Em Fri, Apr 08, 2022 at 12:16:36PM +0300, Adrian Hunter escreveu:
> On 08/04/2022 11.47, Chengdong Li wrote:
> > From: Chengdong Li <chengdongli@...cent.com>
> > 
> > By default `perf test tsc` does not return the error message
> > when the child process detected kernel does not support. Instead,
> > the child process print error message to stderr, unfortunately
> > the stderr is redirected to /dev/null when verbose <= 0.
> > 
> > This patch did three things:
> > - returns TEST_SKIP to the parent process instead of TEST_OK when
> >   perf_read_tsc_conversion() is not supported.
> > - add a new subtest of testing if TSC is supported on current
> >   architecture by moving exist code to a separate function.
> >   It avoids two places in test__perf_time_to_tsc() that return
> >   TEST_SKIP by doing this.
> > - extended test suite definition to contain above two subtests.
> >   Current test_suite and test_case structs do not support printing
> >   skip reason when the number of subtest less than 1. To print skip
> >   reason, it is necessary to extend current test suite definition.
> > 
> > Changes since v3:
> > - refine commit message again to make it clear. 
> > 
> > Changes since v2:
> > - refine error message format.
> > - refine commit log message according to Adrian's review comments.
> > 
> > Changes since v1 (thanks for the feedback from Adrian Hunter):
> > - rebase commit to current source.
> > 
> > Signed-off-by: Chengdong Li <chengdongli@...cent.com>
> 
> Reviewed-by: Adrian Hunter <adrian.hunter@...el.com>

Thanks, applied.

- Arnaldo

 
> > ---
> >  tools/perf/tests/perf-time-to-tsc.c | 36 +++++++++++++++++++++--------
> >  1 file changed, 27 insertions(+), 9 deletions(-)
> > 
> > diff --git a/tools/perf/tests/perf-time-to-tsc.c b/tools/perf/tests/perf-time-to-tsc.c
> > index d12d0ad81801..cc6df49a65a1 100644
> > --- a/tools/perf/tests/perf-time-to-tsc.c
> > +++ b/tools/perf/tests/perf-time-to-tsc.c
> > @@ -47,6 +47,17 @@
> >  	}					\
> >  }
> >  
> > +static int test__tsc_is_supported(struct test_suite *test __maybe_unused,
> > +				  int subtest __maybe_unused)
> > +{
> > +	if (!TSC_IS_SUPPORTED) {
> > +		pr_debug("Test not supported on this architecture\n");
> > +		return TEST_SKIP;
> > +	}
> > +
> > +	return TEST_OK;
> > +}
> > +
> >  /**
> >   * test__perf_time_to_tsc - test converting perf time to TSC.
> >   *
> > @@ -70,7 +81,7 @@ static int test__perf_time_to_tsc(struct test_suite *test __maybe_unused, int su
> >  	struct perf_cpu_map *cpus = NULL;
> >  	struct evlist *evlist = NULL;
> >  	struct evsel *evsel = NULL;
> > -	int err = -1, ret, i;
> > +	int err = TEST_FAIL, ret, i;
> >  	const char *comm1, *comm2;
> >  	struct perf_tsc_conversion tc;
> >  	struct perf_event_mmap_page *pc;
> > @@ -79,10 +90,6 @@ static int test__perf_time_to_tsc(struct test_suite *test __maybe_unused, int su
> >  	u64 test_time, comm1_time = 0, comm2_time = 0;
> >  	struct mmap *md;
> >  
> > -	if (!TSC_IS_SUPPORTED) {
> > -		pr_debug("Test not supported on this architecture");
> > -		return TEST_SKIP;
> > -	}
> >  
> >  	threads = thread_map__new(-1, getpid(), UINT_MAX);
> >  	CHECK_NOT_NULL__(threads);
> > @@ -124,8 +131,8 @@ static int test__perf_time_to_tsc(struct test_suite *test __maybe_unused, int su
> >  	ret = perf_read_tsc_conversion(pc, &tc);
> >  	if (ret) {
> >  		if (ret == -EOPNOTSUPP) {
> > -			fprintf(stderr, " (not supported)");
> > -			return 0;
> > +			pr_debug("perf_read_tsc_conversion is not supported in current kernel\n");
> > +			err = TEST_SKIP;
> >  		}
> >  		goto out_err;
> >  	}
> > @@ -191,7 +198,7 @@ static int test__perf_time_to_tsc(struct test_suite *test __maybe_unused, int su
> >  	    test_tsc >= comm2_tsc)
> >  		goto out_err;
> >  
> > -	err = 0;
> > +	err = TEST_OK;
> >  
> >  out_err:
> >  	evlist__delete(evlist);
> > @@ -200,4 +207,15 @@ static int test__perf_time_to_tsc(struct test_suite *test __maybe_unused, int su
> >  	return err;
> >  }
> >  
> > -DEFINE_SUITE("Convert perf time to TSC", perf_time_to_tsc);
> > +static struct test_case time_to_tsc_tests[] = {
> > +	TEST_CASE_REASON("TSC support", tsc_is_supported,
> > +			 "This architecture does not support"),
> > +	TEST_CASE_REASON("Perf time to TSC", perf_time_to_tsc,
> > +			 "perf_read_tsc_conversion is not supported"),
> > +	{ .name = NULL, }
> > +};
> > +
> > +struct test_suite suite__perf_time_to_tsc = {
> > +	.desc = "Convert perf time to TSC",
> > +	.test_cases = time_to_tsc_tests,
> > +};

-- 

- Arnaldo