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SubjectRe: [PATCH v2 1/5] perf record: Set PERF_RECORD_PERIOD if attr->freq is set.
Em Tue, Jul 28, 2020 at 01:57:30AM -0700, Ian Rogers escreveu:
> From: David Sharp <dhsharp@google.com>
>
> evsel__config() would only set PERF_RECORD_PERIOD if it set attr->freq

There is no such thing as 'PERF_RECORD_PERIOD', its PERF_SAMPLE_PERIOD,
also...

> from perf record options. When it is set by libpfm events, it would not
> get set. This changes evsel__config to see if attr->freq is set outside of
> whether or not it changes attr->freq itself.
>
> Signed-off-by: David Sharp <dhsharp@google.com>
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> tools/perf/util/evsel.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index ef802f6d40c1..811f538f7d77 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -979,13 +979,18 @@ void evsel__config(struct evsel *evsel, struct record_opts *opts,
> if (!attr->sample_period || (opts->user_freq != UINT_MAX ||
> opts->user_interval != ULLONG_MAX)) {
> if (opts->freq) {
> - evsel__set_sample_bit(evsel, PERIOD);
> attr->freq = 1;
> attr->sample_freq = opts->freq;
> } else {
> attr->sample_period = opts->default_interval;
> }
> }
> + /*
> + * If attr->freq was set (here or earlier), ask for period
> + * to be sampled.
> + */
> + if (attr->freq)
> + evsel__set_sample_bit(evsel, PERIOD);

Why can't the libpfm code set opts?

With this patch we will end up calling evsel__set_sample_bit(evsel,
PERIOD) twice, which isn't a problem but looks strange.

- Arnaldo

>
> if (opts->no_samples)
> attr->sample_freq = 0;
> --
> 2.28.0.163.g6104cc2f0b6-goog
>

--

- Arnaldo

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