Re: [PATCH 1/2 -tip] perf_counter: Add generalized hardware vectored co-processor support for AMD and Intel Corei7/Nehalem

Ingo Molnar
2009-07-04T09:50:07Z

* Jaswinder Singh Rajput <jaswinder@kernel.org> wrote:

> On Fri, 2009-07-03 at 12:29 +0200, Ingo Molnar wrote:
> > * Jaswinder Singh Rajput <jaswinder@kernel.org> wrote:
> >
> > > Performance counter stats for '/usr/bin/rhythmbox /home/jaswinder/Music/singhiskinng.mp3':
> > >
> > > 17552264 vec-adds (scaled from 66.28%)
> > > 19715258 vec-muls (scaled from 66.63%)
> > > 15862733 vec-divs (scaled from 66.82%)
> > > 23735187095 vec-idle-cycles (scaled from 66.89%)
> > > 11353159 vec-stall-cycles (scaled from 66.90%)
> > > 36628571 vec-ops (scaled from 66.48%)
> >
> > Is stall-cycles equivalent to busy-cycles?
>
>
> hmm, normally we can use these terms interchangeably. But they can
> be different some times.
>
> busy means it is already executing some instructions so it will
> not take another instruction.
>
> stall can be busy(executing) or non-executing may be it is waiting
> for some operands due to cache miss.
>
>
> > I.e. do we have this
> > general relationship to the cycle event:
> >
> > cycles = vec-stall-cycles + vec-idle-cycles
> >
> > ?
>
> This patch is already big enough, having 206 lines. Do you want
> everything in this patch ;-)

The question i asked is whether the above relationship is true. You
can test this by displaying the 'cycles' metric too in your test,
alongside vec-stall-cycles and vec-idle-cycles. Do the numbers add
up?

Ingo