From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>,
alexander.shishkin@linux.intel.com, namhyung@kernel.org,
yao.jin@linux.intel.com, linux-kernel@vger.kernel.org,
yuzhoujian@didichuxing.com, tmricht@linux.vnet.ibm.com,
anton@samba.org
Subject: Re: [PATCH] perf stat: Fix shadow stats for clock events
Date: Mon, 26 Nov 2018 15:45:40 -0300 [thread overview]
Message-ID: <20181126184540.GC5518@kernel.org> (raw)
In-Reply-To: <20181116133555.GA30465@krava>
Em Fri, Nov 16, 2018 at 02:35:55PM +0100, Jiri Olsa escreveu:
> On Fri, Nov 16, 2018 at 09:58:43AM +0530, Ravi Bangoria wrote:
> > Commit 0aa802a79469 ("perf stat: Get rid of extra clock display
> > function") introduced scale and unit for clock events. Thus,
> > perf_stat__update_shadow_stats() now saves scaled values of
> > clock events in msecs, instead of original nsecs. But while
> > calculating values of shadow stats we still consider clock
> > event values in nsecs. This results in a wrong shadow stat
> > values. Ex,
> >
> > # ./perf stat -e task-clock,cycles ls
> > <SNIP>
> > 2.60 msec task-clock:u # 0.877 CPUs utilized
> > 2,430,564 cycles:u # 1215282.000 GHz
> >
> > Fix this by saving original nsec values for clock events in
> > perf_stat__update_shadow_stats(). After patch:
> >
> > # ./perf stat -e task-clock,cycles ls
> > <SNIP>
> > 3.14 msec task-clock:u # 0.839 CPUs utilized
> > 3,094,528 cycles:u # 0.985 GHz
> >
> > Reported-by: Anton Blanchard <anton@samba.org>
> > Suggested-by: Jiri Olsa <jolsa@redhat.com>
> > Fixes: 0aa802a79469 ("perf stat: Get rid of extra clock display function")
> > Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
>
> Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Thanks, applied.
- Arnaldo
next prev parent reply other threads:[~2018-11-27 12:36 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-15 9:55 [PATCH 1/2] perf stat: Use perf_evsel__is_clocki() for clock events Ravi Bangoria
2018-11-15 9:55 ` [RFC 2/2] perf stat: Fix shadow stats " Ravi Bangoria
2018-11-15 14:17 ` Jiri Olsa
2018-11-16 4:28 ` [PATCH] " Ravi Bangoria
2018-11-16 13:35 ` Jiri Olsa
2018-11-26 18:45 ` Arnaldo Carvalho de Melo [this message]
2018-11-27 8:20 ` Ravi Bangoria
2018-11-27 12:37 ` Arnaldo Carvalho de Melo
2018-12-14 20:19 ` [tip:perf/core] " tip-bot for Ravi Bangoria
2018-12-18 13:46 ` tip-bot for Ravi Bangoria
2018-11-15 13:55 ` [PATCH 1/2] perf stat: Use perf_evsel__is_clocki() " Jiri Olsa
2018-11-15 19:22 ` Arnaldo Carvalho de Melo
2018-11-22 7:13 ` [tip:perf/core] " tip-bot for Ravi Bangoria
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