linux-kernel - Re: [RFCv2 00/48] perf tools: Add threads to record command

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Date:   Fri, 14 Sep 2018 10:28:58 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Alexey Budankov <alexey.budankov@...ux.intel.com>
Cc:     Jiri Olsa <jolsa@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Andi Kleen <andi@...stfloor.org>
Subject: Re: [RFCv2 00/48] perf tools: Add threads to record command

On Fri, Sep 14, 2018 at 10:26:53AM +0200, Jiri Olsa wrote:

SNIP

> > > The threaded monitoring currently can't monitor backward maps
> > > and there are probably more limitations which I haven't spotted
> > > yet.
> > > 
> > > So far I tested on laptop:
> > >   http://people.redhat.com/~jolsa/record_threads/test-4CPU.txt
> > > 
> > > and a one bigger server:
> > >   http://people.redhat.com/~jolsa/record_threads/test-208CPU.txt
> > > 
> > > I can see decrease in recorded LOST events, but both the benchmark
> > > and the monitoring must be carefully configured wrt:
> > >   - number of events (frequency)
> > >   - size of the memory maps
> > >   - size of events (callchains)
> > >   - final perf.data size
> > > 
> > > It's also available in:
> > >   git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
> > >   perf/record_threads
> > > 
> > > thoughts? ;-) thanks
> > > jirka
> > 
> > It is preferable to split into smaller pieces that bring 
> > some improvement proved by metrics numbers and ready for 
> > merging and upstream. Do we have more metrics than the 
> > data loss from trace AIO patches?
> 
> well the primary focus is to get more events in,
> so the LOST metric is the main one

actualy I was hoping, could you please run it through the same
tests as you do for AIO code on some huge server? 

thanks,
jirka