On 1/15/24 16:34, Michel Dänzer wrote:
On 2024-01-15 17:19, Friedrich Vock wrote:
On 15.01.24 16:43, Joshua Ashton wrote:
On 1/15/24 15:25, Michel Dänzer wrote:
On 2024-01-15 14:17, Christian König wrote:
Am 15.01.24 um 12:37 schrieb Joshua Ashton:
On 1/15/24 09:40, Christian König wrote:
Am 13.01.24 um 15:02 schrieb Joshua Ashton:
Without this feedback, the application may keep pushing through
the soft
recoveries, continually hanging the system with jobs that timeout.
Well, that is intentional behavior. Marek is voting for making
soft recovered errors fatal as well while Michel is voting for
better ignoring them.
I'm not really sure what to do. If you guys think that soft
recovered hangs should be fatal as well then we can certainly do
this.
A possible compromise might be making soft resets fatal if they
happen repeatedly (within a certain period of time?).
No, no and no. Aside from introducing issues by side effects not
surfacing and all of the stuff I mentioned about descriptor buffers,
bda, draw indirect and stuff just resulting in more faults and hangs...
You are proposing we throw out every promise we made to an application
on the API contract level because it "might work". That's just wrong!
Let me put this in explicit terms: What you are proposing is in direct
violation of the GL and Vulkan specification.
You can't just chose to break these contracts because you think it
'might' be a better user experience.
Is the original issue that motivated soft resets to be non-fatal even an
issue anymore?
If I read that old thread correctly, the rationale for that was that
assigning guilt to a context was more broken than not doing it, because
the compositor/Xwayland process would also crash despite being unrelated
to the hang.
With Joshua's Mesa fixes, this is not the case anymore, so I don't think
keeping soft resets non-fatal provides any benefit to the user experience.
The potential detriments to user experience have been outlined multiple
times in this thread already.
(I suppose if the compositor itself faults it might still bring down a
session, but I've literally never seen that, and it's not like a
compositor triggering segfaults on CPU stays alive either.)
That's indeed what happened for me, multiple times. And each time the session continued running fine for days after the soft reset.
But apparently my experience isn't valid somehow, and I should have been forced to log in again to please the GL gods...
Conversely, I can't remember hitting a case where an app kept running into soft resets. It's almost as if different people may have different experiences! ;)
Your anecdote of whatever application coincidentally managing to soldier
through being hung is really not relevant.
The right thing to do is to not break all of our api contracts with the
application and not egregiously violate the VK and GL specs. :-)
No-one is saying your session should go down.
It looks like Mutter already has some handling for GL robustness anyway...
So this should already just work with these patches if it is not broken?
- Joshie 🐸✨
Note that I'm not saying that case can't happen. Making soft resets fatal only if they happen repeatedly could address both issues, rather than only one or the other. Seems like a win-win.
