Gang submit

[Liu, Monk]

[AMD Official Use Only - General]

Hi Christian


> A gang submission guarantees that multiple IBs can run on different engines at the same time.
> The effect is that as long as members of a gang are waiting to be submitted no other gang can start pushing jobs to the hardware and so deadlocks are effectively prevented.

Could you please help to explain or confirm:

1) If one gfx ib and one compute ib are in a gang, can they run literally  in parallel on GPU ? 
2) if one gfx ib and one compute ib are belong to two gang, they will be put to the gfx and compute ring one by one (e.g:  gang1-gfx-ib scheduled and signaled, and then gang2-compute-ib scheduled )

Thanks 
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-----Original Message-----
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Christian König
Sent: 2022年3月3日 16:23
To: amd-gfx at lists.freedesktop.org; Olsak, Marek <Marek.Olsak at amd.com>
Subject: Gang submit

Hi guys,

this patch set implements the the requirement for so called gang submissions in the CS interface.

A gang submission guarantees that multiple IBs can run on different engines at the same time.

This is implemented by keeping a global per-device gang around represented by a dma_fence which signals as soon as all jobs in a gang are pushed to the hardware.

The effect is that as long as members of a gang are waiting to be submitted no other gang can start pushing jobs to the hardware and so deadlocks are effectively prevented.

The whole set is based on top of my dma_resv_usage work and a few patches merged over from amd-staging-drm-next, so it won't easily apply anywhere.

Please review and comment,
Christian.