[Intel-gfx] Performance regression using Firefox between 2.14 and 2.15

[Chris Wilson]

On Thu, 29 Sep 2011 16:42:39 +0200, Clemens Eisserer <linuxhippy at gmail.com> wrote:
> I was able to bisect the performance regression, the commit which
> introduced it was:
> 
> commit 686018f283f1d131073ef5917213e6a8ac013f26
> Author: Chris Wilson <chris at chris-wilson.co.uk>
> Date:   Tue Apr 12 08:23:04 2011 +0100
> 
>     Turn relaxed-fencing off by default for older (pre-G33) chipset
> 
> Are there plans to re-enable relaxed fencing again?

We think we've fixed all the related bugs in the kernel, so you can try
flipping the switch and see what happens.

However, I think your symptoms are only a side-effect of disabling relaxed
fencing. The cause is actually more likely to be the use of an untiled
buffer for an image with a stride of greater then 4096 bytes. With relaxed
fencing there is less likelihood of any such buffers being present and so
reused for textures.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre