Threaded OpenGL Dispatch Lands In Mesa 17.1

[Kohrias]

I wonder if this will affect Civ 6 ...

[pal666]

is this only for gallium?

does it matter? intel will be gpu-bound anyway

[pal666]

It is performance enhancement feature same like disk cache

unlike

[pal666]

For games that already dispatch threads properly, which is the majority of them nowadays, it hurts badly.

1) i want to play aspyr games too
2) care to share some numbers of hurt?
3) i heard nvidia enables it by default, so it is possible to implement it properly

[pal666]

I wonder if this will affect Civ 6 ...

yes .

[grigi]

So, I want to share my testing using mesa_glthread=true using Hitman on my notebook with a mobile Firegl M4000 (cape verde 512 shaders 675Mhz) + i7-3720QM (2.6Ghz turbos up-to 3.4Ghz).
Kernel 4.10.1 radeon driver (amdgpu has weird power management issues, and often the screen never switches on after idle), Plasma 5.9 with compositor enabled.
Using the built-in benchmark, all settings on low, 1280x720, no vsync.

Mesa 17.0.1, LLVM 3.9.1-r1:
24.12fps (Stuttery, noticeable input lag)
Mesa Git, LLVM 3.9.1-r1:
Without GLThread, Cold cache: 19.52fps (Extremely stuttery)
Without GLThread, Warm cache: 22.93fps (Less stuttery, but fps/movement seems to suffer from a kind of jitter)
With GLThread, Cold cache: 20.38fps (Noticeable pauses at scene changes, noticeably smoother)
With GLThread, Warm cache: 23.59fps (Got rid of most stutters, now I just wish the performance was better)

From this I can conclude the following:
a. There is a base level performance drop in Mesa git. I expected the without GLThread cached to be slightly higher. It is definitely lower.
b. The caching helps with scene changes, but not much actual change in how the game feels.
c. the threaded dispatcher REALLY smooths out stutters, and makes the game go from super frustrating to play, to enjoyable. This is very promising!

Well done Mesa team :-)
And I'm playing the game with a GPU that is ~1/3 of the performance level than the minimum supported. So the minimum supported specs is actually quite high.

Now I'm wondering if there is anything I can do to get more performance...

[ResponseWriter]

Playing Borderlands 2 with mesa_glthread=true feels a lot smoother now even if the framerate might be lower (I haven't checked but lordheavy reported lower FPS in BL2). Since it has just been merged it will likely have more focus in the remaining month before the merge window closes.

Edit: in other news, I get a GPU hang in Ark:SE on launch with glthread enabled. Haven't tracked down any error message yet.

Edit: With any luck that's related to the crashes in the Piglit suite Mr Arceri is working on right now (thanks!). If not I'll try logging after those patches land.

Edit: With 124ec417f9 applied ARK still crashes at start but this time the screen goes to black. Runs OK without glthread.

[smitty3268]

1) i want to play aspyr games too

Yeah, this is a big deal for aspyr ports.

i heard nvidia enables it by default, so it is possible to implement it properly

They do that by having the driver automatically detect when it's slowing things down and dynamically disable it. That's certainly possible on the Mesa side too, but it's best to get something working out there first and look into improving the heuristics later once the effects across various games are better understood. It took Nvidia years to get to that point, for a really long time they relied on a white list as well.

[pal666]

And I'm playing the game with a GPU that is ~1/3 of the performance level than the minimum supported.

well, both cache and glthread are addressing cpu issues. how fast is your cpu compared to requirements?

[grigi]

well, both cache and glthread are addressing cpu issues. how fast is your cpu compared to requirements?

CPU is right about at minimum. CPU's didn't really improve in performance in the last 6 years.
The thing is, these fixes addresses smoothness, which makes the game much more enjoyable.