[Intel-gfx] Time for execbuf3 ?

[Lionel Landwerlin]

On 21/03/2019 09:46, Joonas Lahtinen wrote:
> Quoting Lionel Landwerlin (2019-03-19 18:39:52)
>> Hi all,
>>
>> There are couple of extensions coming up for our userspace drivers (anv/i965)
>> where we need to add additional parameters to execbuf :
>>
>>      - VK_KHR_timeline_semaphore : supplying u64 points together with syncobjs
>>      [1]
>>      - a non public piece of work related to performance counters [2] :
>>      supplying a performance configuration ID to reconfigure the performance HW
>>
>>
>> Recently some discussions on IRC also highlighted the need for better reporting
>> of execbuf failure.
>> We have a number of bugs where execbuf fails after a number of hours running an
>> application or some random conditions and it's almost impossible to figure out
>> where the problem lies.
>> Having a way for i915 to report what validation the input parameters actually
>> fail would more helpful than EINVAL.
>>
>> Some of the virtual engine stuff could also fit in there but maybe the timeline
>> is too tight for that.
>>
>> We've added a i915_query mechanism that is easily extendable and after exposing
>> topology, it seems to be useful for adding other types of queries (engine
>> discovery, memory regions and the series in [2] also exposes performance query
>> configuration data).
>>
>> I would really like to see a similar mechanism for an execbuf3.
>> How can we help getting started in that direction?
> The direction has certainly been considered for a while already, it's
> mostly a matter of gathering all the requirements to avoid execbuf4 next
> year :)
>
> So if you have any other potential requirements, now is a good time to
> mention them.
>
> Regards, Joonas


Mostly it's just about having the ability to extend it.
I can't really tell you up front what we're going to need until we do :)

Do you know when that work would start?

Thanks

-Lionel

>
>> Do people have a better idea?
>>
>> Thanks,
>>
>> -Lionel
>>
>> [1] : https://github.com/djdeath/linux/commit/
>> 8f26fca6dc41d98cb01c5758be01e382a72c84aa
>> [2] : https://github.com/djdeath/linux/commit/
>> 58be37aae22f7b9b31792aa13415cb5809087c10