[Mesa-dev] [PATCH 0/9] Skip automatic execsize for instructions with a width of 4

[Mark Janes]

Iago Toral <itoral at igalia.com> writes:

> On Wed, 2016-03-09 at 09:54 +0200, Pohjolainen, Topi wrote:
>> On Mon, Mar 07, 2016 at 10:48:49AM +0100, Samuel Iglesias Gons?lvez wrote:
>> > Hello,
>> > 
>> > There is only one patch from this series that has been reviewed (patch
>> > 1).
>> > 
>> > Our plans is to start sending patches for adding fp64 support to i965
>> > driver in the coming weeks but they depend on these patches.
>> > 
>> > Can someone take a look at them? ;)
>> > 
>> > Sam
>> > 
>> > 
>> > On Thu, 2015-12-17 at 14:44 +0100, Samuel Iglesias Gonsálvez wrote:
>> > > Hello,
>> > > 
>> > > This patch series is a updated version of the one Iago sent last
>> > > week [0] that includes patches for gen6 too, as suggested by Jason.
>> > > 
>> > > We checked the gen9 code paths that work with a horizontal width of 4
>> > > and we think there won't be any regression on gen9... but we don't
>> > > have any gen9 machine to run piglit with these patches. Can someone
>> > > check it?
>> 
>> I rebased it and ran it through the test system, gen9 seems to be fine, I
>> only got one regression, and that was on old g965:
>> 
>> /tmp/build_root/m64/lib/piglit/bin/ext_framebuffer_multisample-accuracy all_samples srgb depthstencil -auto -fbo
>> Pixels that should be unlit
>>   count = 236444
>>   RMS error = 0.025355
>> Pixels that should be totally lit
>>   count = 13308
>>   Perfect output
>> The error threshold for unlit and totally lit pixels test is 0.016650
>> Pixels that should be partially lit
>>   count = 12392
>>   RMS error = 0.273876
>> The error threshold for partially lit pixels is 0.333000
>> Samples = 0, Result = fail
>
> I managed to borrow gen4 hardware to test this. According to glxinfo:
> Mesa DRI Mobile Intel GM45 Express Chipset
>
> but it does not fail for me... never. I left this test running in a loop
> for 5 minutes and it never failed. Also, looking at the problem
> described in the output you pasted above, it seems that the problem was
> related to precision calculations and it looks rather odd that our
> execsize patches could've compromised the precision of anything...
>
> Mark, would it be possible for you or someone else to run the piglit
> test mentioned by Topi above on gen4 hardware against this Mesa branch?:
> https://github.com/Igalia/mesa/tree/i965-fix-execsize

I ran this branch through our CI, and it passed all tests.  My
recollection is that ext_framebuffer_multisample-accuracy occasionally
fails on g965.  I would not attribute any failure of that test to this
branch.

> BTW, I also tried to run this inside a larger piglit run (all.py with -t
> framebuffer selects 910 tests, just in case the result could be alatered
> by parallel runs) and same result, it always passes fine.
>
> Iago