Poor compositing performance on 965Q chipset with intel 2.2.1 driver
Barry Scott
barry.scott at onelan.co.uk
Fri May 9 09:48:44 PDT 2008
Michel Dänzer wrote:
> On Fri, 2008-05-09 at 18:35 +0300, Marius Gedminas wrote:
>
>> On Fri, May 09, 2008 at 07:39:47AM -0700, Keith Packard wrote:
>>
>>> On Fri, 2008-05-09 at 14:11 +0100, Barry Scott wrote:
>>>
>>>
>>>> Using latest libpciaccess makes no difference MTRR status is the same:
>>>>
>>> It's not the MTRRs that are broken, it's the page mapping which is
>>> setting the ignore cache and write through bits on each page mapped by
>>> libpciaccess. There's a kludge-around which takes advantage of a
>>> different kernel bug to clear those bits. A simple test:
>>>
>>> $ x11perf -shmput500
>>>
>>> If that gives you a number significantly less than 1000, then your pages
>>> are probably mis-mapped.
>>>
>> Which number is that? The # per second?
>>
>> mg at platonas:~ $ x11perf -shmput500
>> x11perf - X11 performance program, version 1.5
>> The X.Org Foundation server version 10400090 on :0.0
>> from platonas
>> Fri May 9 18:31:46 2008
>>
>> Sync time adjustment is 0.0309 msecs.
>>
>> 3200 reps @ 1.6794 msec ( 595.0/sec): ShmPutImage 500x500 square
>> 3200 reps @ 1.6568 msec ( 604.0/sec): ShmPutImage 500x500 square
>> 3200 reps @ 1.7887 msec ( 559.0/sec): ShmPutImage 500x500 square
>> 3200 reps @ 1.6947 msec ( 590.0/sec): ShmPutImage 500x500 square
>> 3200 reps @ 1.6732 msec ( 598.0/sec): ShmPutImage 500x500 square
>> 16000 trep @ 1.6986 msec ( 589.0/sec): ShmPutImage 500x500 square
>>
>> This is with GM965 and intel driver 2.2.1, but I haven't noticed poor
>> compositing performance.
>>
>
> EXA in xserver 1.4 had a less optimized ShmPutImage implementation.
>
> I think the mystery could indeed just be due to the different 3D engines
> - the infamous issues covered by Carl Worth's blog posts only affect the
> 965 engine.
>
>
Are you saying that there are accelerations that are done for the Q35
and 945 that the 965Q cannot do?
Barry
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