Re: [PATCH 4/6 -tip] perf_counter: Add Generalized Hardware interrupt support for AMD

Ingo Molnar
2009-07-04T10:23:25Z

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

> On Wed, 2009-07-01 at 13:24 +0200, Ingo Molnar wrote:
> > * Jaswinder Singh Rajput <jaswinder@kernel.org> wrote:
> >
> > >
> > > $ ./perf stat -e interrupts -e masked -e int-pending-mask-cycles -- ls -lR /usr/include/ > /dev/null
> > >
> > > Performance counter stats for 'ls -lR /usr/include/':
> > >
> > > 377 interrupts
> > > 53429936 int-mask-cycles
> > > 1119 int-pending-mask-cycles
> > >
> > > 0.371457539 seconds time elapsed
> >
> > Agreed, this is another useful generalization - and the 'cycles
> > pending' metrics are not retrievable via any software means.
> >
> > We could and should probably add a software counter for hardirqs
> > as wel. That would allow the vector/irqnr information to be
> > passed in, and it would allow architectures without irq metrics
> > in the PMU to have this counter too.
> >
>
> Please let me know that addition of software counter will be in
> this patch or we can do it incrementally after this patch.

It should be in this series. That way we can cross-check whether the
soft counts and the hard counts match up and find potential bugs
that way, etc.

Ingo