On 1/15/24 18:30, Bas Nieuwenhuizen wrote:
On Mon, Jan 15, 2024 at 7:14 PM Friedrich Vock <friedrich.vock@xxxxxx
<mailto:friedrich.vock@xxxxxx>> wrote:
Re-sending as plaintext, sorry about that
On 15.01.24 18:54, Michel Dänzer wrote:
> On 2024-01-15 18:26, Friedrich Vock wrote:
>> [snip]
>> The fundamental problem here is that not telling applications that
>> something went wrong when you just canceled their work midway is an
>> out-of-spec hack.
>> When there is a report of real-world apps breaking because of
that hack,
>> reports of different apps working (even if it's convenient that they
>> work) doesn't justify keeping the broken code.
> If the breaking apps hit multiple soft resets in a row, I've laid
out a pragmatic solution which covers both cases.
Hitting soft reset every time is the lucky path. Once GPU work is
interrupted out of nowhere, all bets are off and it might as well
trigger a full system hang next time. No hang recovery should be able to
cause that under any circumstance.
I think the more insidious situation is no further hangs but wrong
results because we skipped some work. That we skipped work may e.g.
result in some texture not being uploaded or some GPGPU work not being
done and causing further errors downstream (say if a game is doing
AI/physics on the GPU not to say anything of actual GPGPU work one might
be doing like AI)
Even worse if this is compute on eg. OpenCL for something
science/math/whatever related, or training a model.
You could randomly just get invalid/wrong results without even knowing!
Now imagine this is VulkanSC displaying something in the car dashboard,
or some medical device doing some compute work to show something on a
graph...
I am not saying you should be doing any of that with RADV + AMDGPU, but
it's just food for thought... :-)
As I have been saying, you simply cannot just violate API contracts like
this, it's flatout wrong.
- Joshie 🐸✨
>
>
>> If mutter needs to be robust against faults it caused itself, it
should be robust
>> against GPU resets.
> It's unlikely that the hangs I've seen were caused by mutter
itself, more likely Mesa or amdgpu.
>
> Anyway, this will happen at some point, the reality is it hasn't
yet though.
>
>
