Marek Has Been Taking To AMDGPU LLVM Optimizations

[phoronix]

Phoronix: Marek Has Been Taking To AMDGPU LLVM Optimizations

Well known AMD open-source driver developer Marek Olšák has ruthlessly been optimizing the Radeon Mesa driver stack for years. With RadeonSI getting fine-tuned and already largely outperforming the AMDGPU-PRO OpenGL driver and most of the big ticket improvements complete, it appears his latest focus is on further optimizing the AMDGPU LLVM compiler back-end...

http://www.phoronix.com/scan.php?page=news_item&px=Marek-AMDGPU-LLVM-Tuning

[shmerl]

Is there something wrong with amdgpu/radeonsi for Vega? The Witcher 3 performance in Wine with Vega 56 is around the same as with RX 480, which doesn't look right.

[pal666]

Is there something wrong with amdgpu/radeonsi for Vega? The Witcher 3 performance in Wine with Vega 56 is around the same as with RX 480, which doesn't look right.

which looks cpu-bound

[artivision]

Is there something wrong with amdgpu/radeonsi for Vega? The Witcher 3 performance in Wine with Vega 56 is around the same as with RX 480, which doesn't look right.

Buy a CPU to OC at 5Ghz and not one with more cores at 4Ghz. An i3-7350K is a good choice to OC and keep the consumption down. You can also use mesa_glthread=true together with CSMT.

[ua=42]

Is there something wrong with amdgpu/radeonsi for Vega? The Witcher 3 performance in Wine with Vega 56 is around the same as with RX 480, which doesn't look right.

The port is CPU bound. So having more gpu doesn't really help the fps at all.

[shmerl]

which looks cpu-bound

It's not. In the posted benchmarks, CPU is used around at 50%. See https://www.gamingonlinux.com/forum/.../post_id=12927

From those images, it does look better than RX 480, but not by much.

[geearf]

You can also use mesa_glthread=true together with CSMT.

Wouldn't it be a bad idea to use both? I thought they were doing about the same thing (at a different level of course).

[shmerl]

Wouldn't it be a bad idea to use both? I thought they were doing about the same thing (at a different level of course).

Hard to predict, and can depend on the CPU and particular application. It works pretty well with Ryzen (using both CSMT and mesa_glthread).

[niner]

It's not. In the posted benchmarks, CPU is used around at 50%. See https://www.gamingonlinux.com/forum/.../post_id=12927

From the exact link you posted: "So CPU bound for sure"
50 % CPU simply means that only half of the available cores are maxed out. Using one of 8 available CPU cores would give you 12.5 % CPU utilization.
Also in the thread it's mentioned, that the GPU does not even switch to maximum clock rate, indicating that it doesn't get new commands fast enough to warrant that.

[lem79]

I love the hardware "GPUTach" feature of my Vega 56. I can quickly and easily tell how loaded the GPU is by simply looking down at my case and seeing how many LEDs are lit up. Brilliant feature that I hope continues to appear on future AMD cards. I've been surprised a few times when I think the GPU is loaded, but GPUTach only shows 50%. That's how I know something else is limiting frames.