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Date: Tue, 12 Nov 2013 17:40:39 +0900 From: Namhyung Kim <namhyung@...nel.org> To: Adrian Hunter <adrian.hunter@...el.com> Cc: Arnaldo Carvalho de Melo <acme@...radead.org>, Ingo Molnar <mingo@...nel.org>, linux-kernel@...r.kernel.org, David Ahern <dsahern@...il.com>, Frederic Weisbecker <fweisbec@...il.com>, Jiri Olsa <jolsa@...hat.com>, Mike Galbraith <efault@....de>, Paul Mackerras <paulus@...ba.org>, Peter Zijlstra <peterz@...radead.org>, Stephane Eranian <eranian@...gle.com> Subject: Re: [PATCH 10/10] perf tests: Use lower sample_freq in sw clock event period test Hi Adrian, On Tue, 12 Nov 2013 09:07:36 +0200, Adrian Hunter wrote: > On 11/11/13 22:22, Arnaldo Carvalho de Melo wrote: >> From: Arnaldo Carvalho de Melo <acme@...hat.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@...andy ~]# perf test 19 >> 19: Test software clock events have valid period values : FAILED! >> [root@...andy ~]# 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@...andy ~]# >> >> [root@...andy ~]# 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 Or else, why not using the max_sample_rate as the freq value? Thanks, Namhyung -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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