lkml.org 
[lkml]   [2013]   [Nov]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH 10/10] perf tests: Use lower sample_freq in sw clock event period test
On 11/11/13 22:22, Arnaldo Carvalho de Melo wrote:
> From: Arnaldo Carvalho de Melo <acme@redhat.com>
>
> We were using it at 10 kHz, which doesn't work in machines where somehow
> the max freq was auto reduced by the kernel:
>
> [root@ssdandy ~]# perf test 19
> 19: Test software clock events have valid period values : FAILED!
> [root@ssdandy ~]# perf test -v 19
> 19: Test software clock events have valid period values :
> --- start ---
> Couldn't open evlist: Invalid argument
> ---- end ----
> Test software clock events have valid period values: FAILED!
> [root@ssdandy ~]#
>
> [root@ssdandy ~]# cat /proc/sys/kernel/perf_event_max_sample_rate
> 7000
>
> Reducing it to 500 Hz should be good enough for this test and also
> shouldn't affect what it is testing.
>
> But warn the user if it fails, informing the knob and the freq tried.

Doesn't work for me:

./perf test -v 19
19: Test software clock events have valid period values :
--- start ---
mmap size 528384B
mmap size 528384B
All (0) samples have period value of 1!
---- end ----
Test software clock events have valid period values: FAILED!

But this fixes it:

diff --git a/tools/perf/tests/sw-clock.c b/tools/perf/tests/sw-clock.c
index 93a7139..6664a7c 100644
--- a/tools/perf/tests/sw-clock.c
+++ b/tools/perf/tests/sw-clock.c
@@ -9,7 +9,7 @@
#include "util/cpumap.h"
#include "util/thread_map.h"

-#define NR_LOOPS 1000000
+#define NR_LOOPS 10000000

/*
* This test will open software clock events (cpu-clock, task-clock)

>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: David Ahern <dsahern@gmail.com>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Jiri Olsa <jolsa@redhat.com>
> Cc: Mike Galbraith <efault@gmx.de>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Stephane Eranian <eranian@google.com>
> Link: http://lkml.kernel.org/n/tip-548rhj1uo6xbwnxa95kw3hqe@git.kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
> tools/perf/tests/sw-clock.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/tests/sw-clock.c b/tools/perf/tests/sw-clock.c
> index ed777728dfe7..93a7139ff5f7 100644
> --- a/tools/perf/tests/sw-clock.c
> +++ b/tools/perf/tests/sw-clock.c
> @@ -34,7 +34,7 @@ static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
> .freq = 1,
> };
>
> - attr.sample_freq = 10000;
> + attr.sample_freq = 500;
>
> evlist = perf_evlist__new();
> if (evlist == NULL) {
> @@ -58,8 +58,11 @@ static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
> }
>
> if (perf_evlist__open(evlist)) {
> + const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
> +
> err = -errno;
> - pr_debug("Couldn't open evlist: %s\n", strerror(errno));
> + pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
> + strerror(errno), knob, (u64)attr.sample_freq);
> goto out_delete_maps;
> }
>



\
 
 \ /
  Last update: 2013-11-12 08:41    [W:0.812 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site