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

Mathieu Desnoyers
2010-09-13T19:43:01Z

* Peter Zijlstra (peterz@infradead.org) 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.