linux-kernel - Re: [PATCH v1 03/11] perf: Allow for multiple ring buffers per event

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Date:	Fri, 14 Mar 2014 11:38:32 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Andi Kleen <ak@...ux.intel.com>
Cc:	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
	Frederic Weisbecker <fweisbec@...il.com>,
	Mike Galbraith <efault@....de>,
	Paul Mackerras <paulus@...ba.org>,
	Stephane Eranian <eranian@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Matt Fleming <matt.fleming@...el.com>
Subject: Re: [PATCH v1 03/11] perf: Allow for multiple ring buffers per event

On Mon, Feb 17, 2014 at 06:36:59PM -0800, Andi Kleen wrote:
> > I'm not convinced it needs to be a PERF_RECORD_SAMPLE; but some
> > PERF_RECORD_* type for sure. 
> 
> Adding a header shouldn't be a problem, it's merely wasting 4K.
> 
> > Also it must allow interleaving with other > events.
> 
> But can you describe a concrete use case where interleaving is better?

I really don't want the multi-buffer nonsense proposed. An event gets
_1_ buffer, that's it.

That also means that if someone redirect another event into this buffer,
it needs to just work.

And because its a perf buffer, people expect it to look like one. So
we've got 'wrap' it.


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