perf tests: No need to set attr.sample_freq in the perf time to TSC test

We were asking for a 4kHz sample_freq, making the test fail needlessly
when the system reduced /proc/sys/kernel/perf_event_max_sample_rate
below that.

In this test we only look at the PERF_SAMPLE_TIME fields in PERF_RECORD_
meta events, no need to set sample_freq.

Thanks to Namhyung for suggesting that max_sample_rate could be the
reason for the test failure, seeing the 'perf test -vv' output I sent.

Before:

  # echo 1000 > /proc/sys/kernel/perf_event_max_sample_rate
  # perf test TSC
  45: Test converting perf time to TSC   : FAILED!

After:

  # perf test TSC
  45: Test converting perf time to TSC   : Ok
  # cat /proc/sys/kernel/perf_event_max_sample_rate
  1000

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-lcob05qhawkuvsyuu9g1fld5@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/arch/x86/tests/perf-time-to-tsc.c b/tools/perf/arch/x86/tests/perf-time-to-tsc.c
index a289aa8a083a2294e17fb324ac581e24e52f71b4..9d29ee283ac5334bfd6a529c7a9d226f0db782cd 100644 (file)
--- a/tools/perf/arch/x86/tests/perf-time-to-tsc.c
+++ b/tools/perf/arch/x86/tests/perf-time-to-tsc.c
@@ -41,7 +41,6 @@ int test__perf_time_to_tsc(int subtest __maybe_unused)
                .mmap_pages          = UINT_MAX,
                .user_freq           = UINT_MAX,
                .user_interval       = ULLONG_MAX,
-               .freq                = 4000,
                .target              = {
                        .uses_mmap   = true,
                },