From: Jiri Olsa <jolsa@redhat.com>
To: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
mark.rutland@arm.com, alexander.shishkin@linux.intel.com,
namhyung@kernel.org, linux-kernel@vger.kernel.org,
linux-perf-users@vger.kernel.org
Subject: Re: [PATCH v2 1/2] libperf: Add processing to scale the counters obtained during the read() system call when multiplexing
Date: Wed, 22 Sep 2021 23:34:51 +0200 [thread overview]
Message-ID: <YUuhe7e0J0PSea+b@krava> (raw)
In-Reply-To: <20210922101627.3396398-2-nakamura.shun@fujitsu.com>
On Wed, Sep 22, 2021 at 07:16:26PM +0900, Shunsuke Nakamura wrote:
> From: nakamura shunsuke <nakamura.shun@fujitsu.com>
>
> perf_evsel__read() scales counters obtained by RDPMC during multiplexing, but
> does not scale counters obtained by read() system call.
>
> Add processing to perf_evsel__read() to scale the counters obtained during the
> read() system call when multiplexing.
>
>
> Signed-off-by: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
> ---
> tools/lib/perf/evsel.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
> index 8441e3e1aaac..0ebd1d34436f 100644
> --- a/tools/lib/perf/evsel.c
> +++ b/tools/lib/perf/evsel.c
> @@ -18,6 +18,7 @@
> #include <sys/ioctl.h>
> #include <sys/mman.h>
> #include <asm/bug.h>
> +#include <linux/math64.h>
>
> void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
> int idx)
> @@ -321,6 +322,11 @@ int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread,
> if (readn(*fd, count->values, size) <= 0)
> return -errno;
>
> + if (count->ena != count->run) {
> + if (count->run != 0)
> + count->val = mul_u64_u64_div64(count->val, count->ena, count->run);
> + }
so I think perf stat expect raw values in there and does the
scaling by itself, please check following code:
read_counters
read_affinity_counters
read_counter_cpu
read_single_counter
evsel__read_counter
perf_stat_process_counter
process_counter_maps
process_counter_values
perf_counts_values__scale
perhaps we could export perf_counts_values__scale if it'd be any help
jirka
> +
> return 0;
> }
>
> --
> 2.27.0
>
next prev parent reply other threads:[~2021-09-22 21:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-22 10:16 [PATCH v2 0/2] libperf: Add support for scaling counters obtained from the read() system call during multiplexing Shunsuke Nakamura
2021-09-22 10:16 ` [PATCH v2 1/2] libperf: Add processing to scale the counters obtained during the read() system call when multiplexing Shunsuke Nakamura
2021-09-22 21:34 ` Jiri Olsa [this message]
2021-09-28 9:53 ` nakamura.shun
2021-10-05 16:36 ` Rob Herring
2021-10-19 4:59 ` nakamura.shun
2021-10-07 17:17 ` Jiri Olsa
2021-10-19 5:00 ` nakamura.shun
2021-11-08 0:49 ` nakamura.shun
2021-11-14 16:16 ` Jiri Olsa
2021-09-22 10:16 ` [PATCH v2 2/2] libperf tests: Add test_stat_multiplexing test Shunsuke Nakamura
2021-10-08 19:11 ` Arnaldo Carvalho de Melo
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