[Intel-gfx] [PATCH v2 3/3] drm/i915: optimise intel_runtime_pm_{get, put}

[Chris Wilson]

On Fri, Nov 18, 2016 at 03:36:47PM +0200, David Weinehall wrote:
> Benchmarking shows that on resume we spend quite a bit of time
> just taking and dropping these references, leaving us two options;
> either rewriting the code not to take these references more than
> once, which would be a rather invasive change since the involved
> functions are used from other places, or to optimise
> intel_runtime_pm_{get,put}().  This patch does the latter.
> Initial benchmarking indicate improvements of a couple
> of milliseconds on resume.
> 
> Original patch by Chris, with slight fixes by me.
> 
> v2: Fix missing return value (Patchwork)
>     Remove extra atomic_dec() (Chris)
> 
> Signed-off-by: David Weinehall <david.weinehall at linux.intel.com>
> CC: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Imre Deak <imre.deak at linux.intel.com>

I'm happy with this. Not amused that it apparently saves quite a bit of
overhead with frequent pm_runtime calls.

Imre?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre