Massive power regression going 3.4->3.5

[James Bottomley]

On Wed, 2012-08-01 at 22:08 -0700, bwidawsk wrote:
> On 2012-08-01 03:06, Chris Wilson wrote:
> > On Wed, 01 Aug 2012 10:38:36 +0100, James Bottomley
> > <James.Bottomley at HansenPartnership.com> wrote:
> >> On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> >> > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
> >> <James.Bottomley at HansenPartnership.com> wrote:
> >> > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> >> > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
> >> <James.Bottomley at HansenPartnership.com> wrote:
> >> > > > > I got the attached to apply and it doesn't really improve 
> >> the idle power
> >> > > > > much (12.5W).
> >> > > >
> >> > > > That's good to know. Next step is to try overriding 
> >> i915.semaphores.
> >> > > > Can you please test with i915.semaphores=0 and 
> >> i915.semaphores=1?
> >> > >
> >> > > There's not much point doing i915_semaphores=1 since that's the 
> >> default
> >> > > on gen 6 hardware, but i915_semaphores=0 recovers and idle power 
> >> of
> >> > > ~6.5W
> >> >
> >> > It is only the default if iommu is off, and changing the default
> >> > was one of the side-effects of the patch you bisected.
> >> >
> >> > Can you please login to the desktop, let it idle, record
> >> > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> >> > Then trace-cmd record -e i915 sleep 10s,
> >>
> >> OK, what is trace-cmd?  It looks similar to perf tools ... is that 
> >> it?
> >
> > Yes, it is roughly equivalent and you should be able to achieve the 
> > same
> > with perf trace - except I haven't done it before so I don't have 
> > quick
> > advice on how to drive it. :)
> > -Chris
> 
> Should be something like:
> perf record -f -g -e i915:* -a

I already sent the output of trace-cmd ... is that enough?

James