On 2025-01-13 12:40, Tvrtko Ursulin wrote:
> On 10/01/2025 09:14, Michel Dänzer wrote:
>> On 2025-01-09 17:55, Tvrtko Ursulin wrote:
>>> On 09/01/2025 15:08, Michel Dänzer wrote:
>>>> On 2025-01-03 13:31, Christian König wrote:
>>>>
>>>>> What FIFO is still missing compared to RR is some sort of fairness 
>>>>> between queues. E.g. a queues which hasn't submitted something in a while 
>>>>> might get a bonus for their submissions compared to a queue which submits 
>>>>> stuff all the time (or something like that).
>>>>
>>>> The lack of that could indeed explain the scenario above, if the game 
>>>> submits its GPU job for frame n+1 before Xwayland submits its GPU job for 
>>>> presenting frame n.
>>>
>>> I would be keen to experiment with this. There is that last patch in v2 of 
>>> my series which scales the deadlines based on queue depth. So for a client 
>>> which submits two frames it could be enough (in principle, not the actually 
>>> posted version) to push out the deadline at qd=2 so a client which never 
>>> breaks qd=1 can reliably overtake it.
>>>
>>> What would really be great if you could suggest me as easy to set up as 
>>> possible test case with objective measuring criteria. And it would have to 
>>> run on AMD. Quake II RTX under XWayland as the GitLab issue suggest or 
>>> there is more to it? Does it has to be GNOME?
>>
>> Don't think it has to be.
>>
>>> Any way to run it programmatically and get a performance number out?
>>
>> This could be tricky, since the game itself reports the same frame rate in 
>> both cases. You'd have to compare the frame times in the compositor instead.
> 
> So missed frames in the compositor?

Rather in Xwayland, the compositor is where it's visible to the user.


>> Also, the issue might no longer be reproducible in this particular scenario 
>> with current Xwayland, because it should no longer do any GPU copies for 
>> presentation but just forward the client buffers to the compositor.
> Do you have an idea how could we find out more about that what you said: 
> "people are saying RR works better than FIFO for some gaming scenarios even 
> with current Xwayland, which shouldn't do any GPU copies for presentation of 
> fullscreen windows"?

Other than asking affected users for more information, not offhand.


-- 
Earthling Michel Dänzer       \        GNOME / Xwayland / Mesa developer
https://redhat.com             \               Libre software enthusiast

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