Re: [PATCH] perf_events: improve DS/BTS/PEBS buffer allocation

From: Mathieu Desnoyers
Date: Mon Sep 13 2010 - 15:43:05 EST


* Peter Zijlstra (peterz@xxxxxxxxxxxxx) wrote:
> On Mon, 2010-09-13 at 15:31 -0400, Mathieu Desnoyers wrote:
> > > Ok, so can we play the same trick you're playing with the sampling
> > > buffer, i.e., you use alloc_pages_node() for one page at a time, and
> > > then you stitch them on demand via SW?
> >
> > Well, a thought is striking me: it sounds like you are re-doing YAORB (short
> > for Yet Another Ring Buffer,
>
> He's not.. the hardware needs a large (virtually) contiguous region to
> poke data into, we need to read it out from NMI context.

Ah ok, it's different then.

Thanks,

Mathieu

--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
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