[Intel-gfx] [PATCH] drm/i915: add a tracepoint for gpu frequency changes
Chris Wilson
chris at chris-wilson.co.uk
Sun Sep 2 09:41:21 CEST 2012
On Sat, 01 Sep 2012 18:16:52 -0700, Ben Widawsky <ben at bwidawsk.net> wrote:
> On 2012-09-01 12:22, Chris Wilson wrote:
> > On Sat, 01 Sep 2012 11:35:13 -0700, Ben Widawsky <ben at bwidawsk.net>
> > wrote:
> >> I have no problem with Daniel's patch. It's just a matter of cutting
> >> through some scheduler BS of "when the GPU wants to change
> >> frequency"
> >> vs. "when we actually change the GPU frequency." I think *both* are
> >> interesting.
> >
> > We already trace the interrupt, which has been invaluable in
> > debugging. And there is no other source currently... :)
> > -Chris
>
> No we do not trace it (/me is looking on cgit, so perhaps a bit error
> prone). Sure we trace GT interrupts, but not pm interrupts (again,
> unless I am missing something via code browsing on the web).
Oh we definitely do otherwise it would have been a bit difficult to have
noticed that we woke up every 10ms to service a PM event that we then
ignore...
> Furthermore, even if we have added a generic interrupt trace event and
> I've missed it: I think it's still nice to have a power/performance
> specific one for users like powerTOP, as opposed to driver developers.
As complete BS as GPU op/s? If you can find a tracepoint that is
actionable from within powertop, go for it.
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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