From: Jiri Olsa <jolsa@redhat.com>
To: David Miller <davem@davemloft.net>
Cc: acme@kernel.org, linux-kernel@vger.kernel.org,
namhyung@kernel.org, jolsa@kernel.org
Subject: Re: [PATCH RFC] hist lookups
Date: Mon, 12 Nov 2018 00:26:27 +0100 [thread overview]
Message-ID: <20181111232627.GC30042@krava> (raw)
In-Reply-To: <20181111.150801.1421291572221954626.davem@davemloft.net>
On Sun, Nov 11, 2018 at 03:08:01PM -0800, David Miller wrote:
> From: Jiri Olsa <jolsa@redhat.com>
> Date: Sun, 11 Nov 2018 20:41:32 +0100
>
> > On Thu, Nov 08, 2018 at 05:07:21PM -0800, David Miller wrote:
> >> From: Jiri Olsa <jolsa@redhat.com>
> >> Date: Thu, 8 Nov 2018 08:13:03 +0100
> >>
> >> > we could separated fork/mmaps to separate dummy event map, or just
> >> > parse them out in the read thread and create special queue for them
> >> > and drop just samples in case we are behind
> >>
> >> What you say at the end here is basically what I am proposing.
> >>
> >> Perf dequeues events from mmap ring as fast as possible.
> >>
> >> Perf has two internal queues, high priority and low priority.
> >>
> >> High priority events are never dropped.
> >>
> >> Low priority events are dropped on overload, oldest first.
> >
> > I added the dropping logic, it's simple so far..
>
> So for me perf top gets into a state where the samples counter stops
> incrementing, but the event counter does keep moving (which is the
> histogram code decaying histogram entries from the display thread).
>
> Which means the event processing has basically stopped.
>
> The event threads are not stuck in a loop, because they respond to
> the "q" keypress and we can exit.
is the drop count showing something?
jirka
next prev parent reply other threads:[~2018-11-11 23:26 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-31 5:03 [PATCH RFC] hist lookups David Miller
2018-10-31 12:43 ` Arnaldo Carvalho de Melo
2018-10-31 15:39 ` Jiri Olsa
2018-10-31 16:08 ` David Miller
2018-11-03 6:30 ` David Miller
2018-11-04 20:18 ` Jiri Olsa
2018-11-05 0:50 ` David Miller
2018-11-05 20:34 ` Jiri Olsa
2018-11-05 22:52 ` David Miller
2018-11-06 3:45 ` David Miller
2018-11-06 4:03 ` David Miller
2018-11-06 4:53 ` David Miller
2018-11-06 11:54 ` Jiri Olsa
2018-11-19 5:26 ` Namhyung Kim
2018-11-19 9:12 ` Jiri Olsa
2018-11-20 1:13 ` Namhyung Kim
2018-11-06 20:42 ` Jiri Olsa
2018-11-07 6:13 ` David Miller
2018-11-07 8:32 ` Jiri Olsa
2018-11-07 19:43 ` Jiri Olsa
2018-11-07 20:01 ` David Miller
2018-11-07 20:28 ` Arnaldo Carvalho de Melo
2018-11-08 6:04 ` David Miller
2018-11-08 7:13 ` Jiri Olsa
2018-11-09 1:07 ` David Miller
2018-11-11 19:41 ` Jiri Olsa
2018-11-11 19:41 ` Jiri Olsa
2018-11-11 22:32 ` David Miller
2018-11-11 22:43 ` Jiri Olsa
2018-11-11 22:58 ` David Miller
2018-11-11 23:08 ` David Miller
2018-11-11 23:26 ` Jiri Olsa [this message]
2018-11-11 23:32 ` David Miller
2018-11-13 10:40 ` Jiri Olsa
2018-11-19 4:52 ` David Miller
2018-11-19 6:28 ` Namhyung Kim
2018-11-19 6:33 ` David Miller
2018-11-19 7:16 ` Namhyung Kim
2018-11-19 9:14 ` Jiri Olsa
2018-11-06 11:51 ` Jiri Olsa
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