Re: [PATCHv2] perf/stat: Report unsupported events properly

From: Arnaldo Carvalho de Melo
Date: Fri Feb 13 2015 - 15:57:44 EST


Em Fri, Feb 13, 2015 at 12:39:24PM -0700, David Ahern escreveu:
>
>
> On 02/13/2015 11:40 AM, Suzuki K. Poulose wrote:
> >From: "Suzuki K. Poulose" <suzuki.poulose@xxxxxxx>
> >
> >Commit 1971f59 (perf stat: Use read_counter in read_counter_aggr )
> >broke the perf stat output for unsupported counters.
> >
> > $ perf stat -v -a -C 0 -e CCI_400/config=24/ sleep 1
> > Warning:
> > CCI_400/config=24/ event is not supported by the kernel.
> >
> > Performance counter stats for 'system wide':
> >
> > 0 CCI_400/config=24/
> >
> > 1.080265400 seconds time elapsed
> >
> >Where it used to be :
> >
> >$ perf stat -v -a -C 0 -e CCI_400/config=24/ sleep 1
> > Warning:
> > CCI_400/config=24/ event is not supported by the kernel.
> >
> > Performance counter stats for 'system wide':
> >
> > <not supported> CCI_400/config=24/
> >
> > 1.083840675 seconds time elapsed
> >
> >This patch fixes the issues by checking if the counter is supported,
> >before reading and logging the counter value.
> >
> >Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> >Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> >Signed-off-by: Suzuki K. Poulose <suzuki.poulose@xxxxxxx>
> >---
> > tools/perf/builtin-stat.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> >diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> >index e598e4e..d28949d 100644
> >--- a/tools/perf/builtin-stat.c
> >+++ b/tools/perf/builtin-stat.c
> >@@ -510,6 +510,9 @@ static int read_counter(struct perf_evsel *counter)
> > int ncpus = perf_evsel__nr_cpus(counter);
> > int cpu, thread;
> >
> >+ if (!counter->supported)
> >+ return -ENOENT;
> >+
> > if (counter->system_wide)
> > nthreads = 1;
> >
> >@@ -1285,7 +1288,7 @@ static void print_counter_aggr(struct perf_evsel *counter, char *prefix)
> > if (prefix)
> > fprintf(output, "%s", prefix);
> >
> >- if (scaled == -1) {
> >+ if (scaled == -1 || !counter->supported) {
> > fprintf(output, "%*s%s",
> > csv_output ? 0 : 18,
> > counter->supported ? CNTR_NOT_COUNTED : CNTR_NOT_SUPPORTED,
> >
>
> Just hit this as well.
>
> Acked-and-Tested-by: David Ahern <dsahern@xxxxxxxxx>

Gack, 10ms after I sent my pre-California pull req :-\

Will go in the next one :-)

- Arnaldo
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