linux-kernel - Re: [PATCH RFC] hist lookups

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Message-ID: <20181119062837.GB20153@sejong>
Date:   Mon, 19 Nov 2018 15:28:37 +0900
From:   Namhyung Kim <namhyung@...nel.org>
To:     David Miller <davem@...emloft.net>
Cc:     jolsa@...hat.com, acme@...nel.org, linux-kernel@...r.kernel.org,
        jolsa@...nel.org, kernel-team@....com
Subject: Re: [PATCH RFC] hist lookups

Hello David,

On Sun, Nov 18, 2018 at 08:52:43PM -0800, David Miller wrote:
> From: Jiri Olsa <jolsa@...hat.com>
> Date: Tue, 13 Nov 2018 11:40:54 +0100
> 
> > I pushed/rebased what I have to perf/fixes branch again
> > 
> > please note I had to change our compile changes, because
> > they wouldn't compile on x86, but I can't verify on sparc,
> > so you might see some compile fails again
> 
> I just checked your current perf/fixes branch.
> 
> It builds on Sparc ;-)
> 
> And it behaves better too.  I do get tons of drops and lost events,
> but it seems to keep going even during the hardest load.
> 
> Eventually I end up with a lot of unresolvable histogram entries,
> so that is something to look into.

Did you record callchains as well?  I'd like to know whether it's
related to the children (cumulative) mode or not.

Thanks,
Namhyung


> 
> I looked at your drop logic and it seems perfect, we avoid dropping
> all non-SAMPLE events which is what we want.  So that can't be the
> cause of the issues I am seeing.
>