[Intel-gfx] [ubuntu-x] -intel 2.6.3 uploaded

[Peter Clifton]

On Tue, 2009-03-24 at 00:15 +0000, Peter Clifton wrote:

[snip]

> Here's a really fun discovery.. I ran a short test program to busy-loop
> the CPU. This is with the "performance" governer. After running one
> copy, my glxgears fps appeared to increase. Curious, I spawned a second
> copy (I have 2 cores of CPU). glxgears fps increased again! (to
> ~950fps). Just for completeness' sake, I'll note that a third copy slows
> it down again somewhat.
> 
> The busy-loop programs are keeping the CPU from idling, and perhaps
> somehow the residency of lower C states is giving rise to the lower
                                                       higher ____^
> frame-rates (in spite the CPU being otherwise busy).

(had originally started to phrase this the other way around.. perhaps
higher C states are causing latency -> lower frame-rates).

-- 
Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA

Tel: +44 (0)7729 980173 - (No signal in the lab!)