From: Jiri Olsa <jolsa@redhat.com>
To: Song Liu <songliubraving@fb.com>
Cc: lkml <linux-kernel@vger.kernel.org>,
kbuild test robot <lkp@intel.com>,
Kernel Team <Kernel-team@fb.com>, Tejun Heo <tj@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Jiri Olsa <jolsa@kernel.org>,
Alexey Budankov <alexey.budankov@linux.intel.com>
Subject: Re: [PATCH v2 1/1] perf: Sharing PMU counters across compatible events
Date: Sun, 23 Sep 2018 23:44:26 +0200 [thread overview]
Message-ID: <20180923214426.GL30923@krava> (raw)
In-Reply-To: <90BE3370-3006-426A-80DC-279F07192E70@fb.com>
On Tue, Sep 11, 2018 at 01:29:32PM +0000, Song Liu wrote:
SNIP
> >>>
> >>> jirka
> >>
> >> I am not sure I am following. The pmu is disabled when we call
> >> event_pmu_add(). Why do we need to read before calling pmu->add()?
> >> And this is the first added dup event for this master, so we don't
> >> need to worry about others.
> >>
> >> Does this make sense?
> >
> > I was just thinking since the pmu is disable we could
> > we don't need to read the event on 2 places.. it's almost
> > identic code
>
> How about something like:
>
>
> +/* PMU sharing aware version of event->pmu->add() */
> +static int event_pmu_add(struct perf_event *event,
> + struct perf_event_context *ctx)
> +{
> + struct perf_event_dup *dup;
> + int ret;
> +
> + /* no sharing, just do event->pmu->add() */
> + if (event->dup_id == -1)
> + return event->pmu->add(event, PERF_EF_START);
> +
> + dup = &ctx->dup_events[event->dup_id];
> +
> + if (dup->active_event_count = 0) {
> + /* try add master */
> + ret = event->pmu->add(dup->master, PERF_EF_START);
> + if (ret)
> + return ret;
> + }
> +
> + dup->active_event_count++;
> + event->pmu->read(dup->master);
> + event->dup_base_count = dup_read_count(dup);
> + event->dup_base_child_count = dup_read_child_count(dup);
> +
> + return 0;
> +}
yep, seems ok
jirka
next prev parent reply other threads:[~2018-09-23 21:44 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-15 17:03 [PATCH v2 0/1] perf: Sharing PMU counters across compatible events Song Liu
2018-08-15 17:03 ` [PATCH v2 1/1] " Song Liu
2018-08-30 15:13 ` Jiri Olsa
2018-08-30 18:35 ` Song Liu
2018-09-10 8:13 ` Jiri Olsa
2018-09-11 13:29 ` Song Liu
2018-09-23 21:44 ` Jiri Olsa [this message]
2018-08-30 15:18 ` Jiri Olsa
2018-08-30 18:51 ` Song Liu
2018-09-10 8:15 ` Jiri Olsa
2018-09-11 13:38 ` Song Liu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180923214426.GL30923@krava \
--to=jolsa@redhat.com \
--cc=Kernel-team@fb.com \
--cc=alexey.budankov@linux.intel.com \
--cc=jolsa@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lkp@intel.com \
--cc=peterz@infradead.org \
--cc=songliubraving@fb.com \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).