[PATCH 32/59] perf tests: No need to set attr.sample_freq in the perf time to TSC test

From: Arnaldo Carvalho de Melo
Date: Fri Jan 08 2016 - 13:21:53 EST


From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

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@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-lcob05qhawkuvsyuu9g1fld5@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/arch/x86/tests/perf-time-to-tsc.c | 1 -
1 file changed, 1 deletion(-)

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 a289aa8a083a..9d29ee283ac5 100644
--- 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,
},
--
2.1.0