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

Peter Zijlstra
2010-09-13T19:34:45Z

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.