Re: [RFC][PATCH] perf_events, x86: PEBS support

From: Stephane Eranian
Date: Wed Feb 03 2010 - 18:51:44 EST


On Thu, Feb 4, 2010 at 12:50 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Wed, 2010-02-03 at 15:40 +0100, Peter Zijlstra wrote:
>>
>> If only they would reset the counter on overflow instead of on record,
>> that would solve quite a few issues I imagine.
>
> So I tried enabling the regular PMC overflow interrupt and reprogramming
> the counter from that, but touching the counter seems to destroy the
> PEBS assist, so much for that idea.
>
Yes, you have to leave the INT bit off, otherwise you get an
interrupt for each overflow, thus you lose the buffer advantage.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/