[Mesa-dev] Time to merge threaded GL dispatch? (aka glthread)

[Marek Olšák]

On Fri, Feb 10, 2017 at 12:26 PM, Edward O'Callaghan
<funfunctor at folklore1984.net> wrote:
>
>
> On 02/08/2017 09:13 AM, Timothy Arceri wrote:
>> On Tue, 2017-02-07 at 10:56 +0100, Marek Olšák wrote:
>>> On Tue, Feb 7, 2017 at 2:57 AM, Kenneth Graunke <kenneth at whitecape.or
>>> g> wrote:
>>>> On Monday, February 6, 2017 8:54:40 PM PST Marek Olšák wrote:
>>>>> On Mon, Feb 6, 2017 at 8:20 PM, Ernst Sjöstrand <ernstp at gmail.com
>>>>>> wrote:
>>>>>> FYI glmark2 segfaults with mesa_glthread=true. Expected that
>>>>>> some programs
>>>>>> will segfault?
>>>>>
>>>>> Yes, even segfaults are expected with mesa_glthread=true.
>>>>>
>>>>> Marek
>>>>
>>>> Would it make sense to be crash-free or even regression-free on at
>>>> least Piglit, before merging?  (Or are we there already?)
>>>
>>> It's not necessary. glthread is disabled by default. Nobody has
>>> tested
>>> piglit with glthread. That will follow after it's been merged, or
>>> never if it's never merged.
>>
>> I've been trying to land shader-cache patches that actually do pass
>> piglit for over a year with the same reasoning that it will be disable
>> by default and can only be improved with testing I can't possibly do on
>> my own.
>>
>> Although I have no objections to this being merged I'll be extremely
>> frustrated if this is allowed to be merged known to not even pass
>> piglit while I've wasted countless hours rebasing shader cache over
>> many months.
>>
>
> Regardless of all the chatter on this thread in and around GL dispatch,
> which I agree poses significant challenges to get into something 'ideal'
> - which is hard to define for something like this..
>
> I think Timothy makes a really fair and just case here; in that, could
> we perhaps prioritize getting the shader cache stuff in before
> attempting GL dispatch? I think this both morally and technically the
> right thing to do in my humble opinion.

There is a small difference. The shader cache is expected to be
enabled by default, so there is a certain level of quality required.
glthread won't likely be enabled by default, because we don't even
know whether that's possible given the difficulty of the task.

The shader cache will likely be merged first anyway.

Marek