Re: [PATCH 2/2] drm/panfrost: adjusted job affinity for dual core group GPUs

[Alyssa Rosenzweig <alyssa@collabora.com>]

> Whether it's worth the effort depends on whether anyone really cares
> about getting the full performance out of this particular GPU.
> 
> At this stage I think the main UABI change would be to add the opposite
> flag to kbase, (e.g. "PANFROST_JD_DOESNT_NEED_COHERENCY_ON_GPU"[1]) to
> opt-in to allowing the job to run across all cores.
> 
> The second change would be to allow compute jobs to be run on the second
> core group, so another flag: PANFROST_RUN_ON_SECOND_CORE_GROUP.
> 
> But clearly there's little point adding such flags until someone steps
> up to do the Mesa work.

I worry about the maintainence burden (both Mesa and kernel) of adding
UABI only used by a piece of hardware none of us own, and only useful
"sometimes" for that hardware. Doubly so for the second core group
support; currently Mesa doesn't advertise any compute support on
anything older than Mali T760 ... to the best of my knowledge, nobody
has missed that support either...

To be clear I am in favour of merging the patches needed for GLES2 to
work on all Malis, possibly at a performance cost on these dual-core
systems. That's a far cry from the level of support the DDK gave these
chips back in the day ... of course, the DDK doesn't support them at all
anymore, so Panfrost wins there by default! ;)