linux-kernel - Re: [PATCH v2] perf: Suppress AUX/OVERWRITE records

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Date:   Fri, 4 May 2018 12:36:40 -0300
From:   Arnaldo Carvalho de Melo <acme@...hat.com>
To:     Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc:     Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
        Will Deacon <will.deacon@....com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Markus Metzger <markus.t.metzger@...el.com>
Subject: Re: [PATCH v2] perf: Suppress AUX/OVERWRITE records

Em Fri, May 04, 2018 at 12:35:34PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Fri, May 04, 2018 at 03:09:59PM +0300, Alexander Shishkin escreveu:
> > On Wed, Apr 04, 2018 at 05:53:23PM +0300, Alexander Shishkin wrote:
> > > It has been pointed out to me many times that it is useful to be able
> > > to switch off AUX records to save the bandwidth for records that actually
> > > matter, for example, in AUX overwrite mode.
> > > 
> > > The usefulness of PERF_RECORD_AUX is in some of its flags, like the
> > > TRUNCATED flag that tells the decoder where exactly gaps in the trace are.
> > > The OVERWRITE flag, on the other hand will be set on every single record
> > > in overwrite mode. However, a PERF_RECORD_AUX[flags=OVERWRITE] is
> > > generated on every target task's sched_out, which over time adds up to
> > > a lot of useless information.
> > > 
> > > If any folks out there have userspace that depends on a constant stream of
> > > OVERWRITE records for a good reason, they'll have to let us know.
> > > 
> > > Signed-off-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
> > > Cc: Markus Metzger <markus.t.metzger@...el.com>
> > > Cc: Adrian Hunter <adrian.hunter@...el.com>
> > 
> > This one seems to be slipping through the cracks.
> 
> So, did you got Acked-by  or tested-by from anyone?

Yeah, tons of them, I'll pick this up

- Arnaldo