Re: [PATCH RFC -tip 0/6] perf: IRQ-bound performance events

[Peter Zijlstra]

On Mon, Jun 03, 2013 at 03:36:19PM +0200, Alexander Gordeev wrote:
> On Mon, Jun 03, 2013 at 11:41:32AM +0200, Alexander Gordeev wrote:
> > # ./tools/perf/perf stat -I 8 -a -e L1-dcache-load-misses:k sleep 1
> > 
> >  Performance counter stats for process id '8':
> > 
> >                  0 L1-dcache-load-misses                                       
> > 
> >        1.001235781 seconds time elapsed
> > 
> > # ./tools/perf/perf stat -I 8 -a -e L1-dcache-load-misses:k hwclock --test
> > Mon 03 Jun 2013 04:42:59 AM EDT  -0.891274 seconds
> > 
> >  Performance counter stats for process id '8':
> 
> Oops, the most interesting part did not make it in. Very sorry :) Here:
> 
> # ./tools/perf/perf stat -I 8 -a -e L1-dcache-load-misses:k hwclock --test
> Mon 03 Jun 2013 09:32:49 AM EDT  -0.719514 seconds
> 
>  Performance counter stats for process id '8':
> 
>                447 L1-dcache-load-misses                                       

I think that is very much expected; except in the case where you spend
_all_ your time in IRQ handlers, they'll pretty much always miss l1
cache.
--
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/