[Intel-gfx] IVB GPU turbo

[Joe Bloggsian]

Hi,

We are looking at accelerating video operations using 
vaapi/intel-driver. When using Ivy bridge we believe that the GPU is 
(almost always) not turboing even when 100% busy doing vaapi video 
things (e.g. image scaling on EUs or bitstream decode). To determined 
this we use cat /sys/kernel/debug/dri/0/i915_cur_delayinfo and GPU top 
(todays IVB fixed vesion). We have tried a variety of IVB parts from 
3610QE up to 3770 - all do the same. We've mainly been using kernel 
3.2.0-24-generic and libdrm 2.4.32. The same machines turbo correctly 
when doing equivent things in windows using intel media SDK.

I get the impression from mailing lists that turbo is known to have 
driver/sw issues. Can anyone suggest if there is a later kernel/drm 
version that might improve things? If so where do we find it? This is 
for evaluation so we're happy to try unstable latest software.

Thanks!
Bloggsian