[Mesa-dev] Mesa (master): 29 new commits

[Marek Olšák]

On Fri, Apr 22, 2016 at 11:28 PM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
> On 22.04.2016 12:29, Nicolai Hähnle wrote:
>>
>> On 20.04.2016 23:02, Michel Dänzer wrote:
>>>
>>> On 21.04.2016 02:42, Marek Olšák wrote:
>>>>
>>>> On Thu, Apr 14, 2016 at 9:29 AM, Michel Dänzer <michel at daenzer.net>
>>>> wrote:
>>>>>
>>>>> On 14.04.2016 11:37, Michel Dänzer wrote:
>>>>>>
>>>>>> On 12.04.2016 21:33, Marek =?UNKNOWN?B?T2zFocOhaw==?= wrote:
>>>>>>>
>>>>>>>
>>>>>>> URL:
>>>>>>>
>>>>>>> http://cgit.freedesktop.org/mesa/mesa/commit/?id=5a4b74d1ba2c156766a7a5dbfef099c7db5d6694
>>>>>>>
>>>>>>> Author: Marek Olšák <marek.olsak at amd.com>
>>>>>>> Date:   Mon Apr 11 19:56:07 2016 +0200
>>>>>>>
>>>>>>>      gallium/radeon: relax requirements on VRAM placements on APUs
>>>>>>
>>>>>>
>>>>>> This change caused a bunch of ARB_shader_load_image_store piglit tests
>>>>>> to fail on my Kaveri, see some examples below. The incorrect values
>>>>>> seem consistent.
>>>>>>
>>>>>> I suppose some buffers end up in GTT instead of VRAM with this
>>>>>> change, but I'm not sure how that could cause problems. Any ideas?
>>>>>
>>>>>
>>>>> Also, with the code modified to use GTT only for everything but
>>>>> (potential) scanout buffers, the performance of Unigine Valley and the
>>>>> Unreal Engine 4 Elemental demo is reduced by about 30%. So the premise
>>>>> that GTT is about as fast as VRAM doesn't seem to hold true in practice
>>>>> (at least with Kaveri and presumably other (pre-)CIK APUs; maybe it's
>>>>> better with Carrizo and newer), which means that this change may cause
>>>>> performance of long-running processes to drop significantly over time.
>>>>>
>>>>> Given all these issues, I'm afraid it may be better to revert this
>>>>> change for now, until we have a better plan for dealing with this.
>>>>
>>>>
>>>> Assuming you use the radeon kernel driver and you are not busy, would
>>>> you please check whether the performance is lower on amdgpu as well?
>>>
>>>
>>> I am using the radeon driver, but also quite busy. Nicolai, can you try
>>> it on your Carrizo?
>>
>>
>> I don't see any difference on Unigine Valley with my Carrizo (512MB of
>> VRAM).
>
>
> I have learned an important lesson today: the Phoronix Test Suite runner
> eats my environment variables (and possibly babies?). So my earlier tests
> were for nothing.
>
> In reality, Unigine Valley gains about 30% frame rate with the VRAM_GTT
> placement.

It looks like we do need Kaveri results on amdgpu to know if CIK or
radeon is the issue. Then, we can either turn it off for radeon or
CIK.

Marek