AMDGPU/Radeon For Linux 4.5 Drops UMS Support, Brings Optimizations

[phoronix]

Phoronix: AMDGPU/Radeon For Linux 4.5 Drops UMS Support, Brings Optimizations

Just minutes after writing about how AMDGPU PowerPlay support made it into AMD's drm-next-4.5 branch, that Git branch is now called for pulling into DRM-Next. Besides the PowerPlay support for the latest Radeon GPUs, there are also a number of other changes...

http://www.phoronix.com/scan.php?page=news_item&px=Linux-4.5-Pull-AMD-DRM

[CrystalGamma]

Just to confirm: AMDGPU never had UMS support, right? That part is just about radeon.ko, right?
If it is, then I fully welcome this. Those people who do use radeon.ko with UMS probably maintain their own kernel anyway ...

[cbxbiker61]

Linux 4.5's release will render the limited benchmarks that Michael has done on Carrizo invalid, since it will be the first version that supports Carrizo/PowerPlay.

Looking at the check-ins for 4.5 the Carrizo/PowerPlay changes are significant.

[agd5f]

Linux 4.5's release will render the limited benchmarks that Michael has done on Carrizo invalid, since it will be the first version that supports Carrizo/PowerPlay.

Looking at the check-ins for 4.5 the Carrizo/PowerPlay changes are significant.

Carrizo had power management support in the initial amdgpu release. This just adds carrizo support to the new powerplay component.

[CrystalGamma]

Carrizo had power management support in the initial amdgpu release. This just adds carrizo support to the new powerplay component.

What's the difference between PowerPlay and power management?

[agd5f]

What's the difference between PowerPlay and power management?

They both control power management on the GPU. The original code was a port of the power management infrastructure from radeon. The new powerplay code leverages the powerplay component from the closed source driver more heavily.

[SystemCrasher]

They both control power management on the GPU. The original code was a port of the power management infrastructure from radeon. The new powerplay code leverages the powerplay component from the closed source driver more heavily.

And what are major differences between DPM and PowerPlay on purely technical layer? I.e. are they anyhow different in terms of voltage/freq scaling, etc from practical standpoint?

[Kano]

@agd5f

Why is Fiji still so extremely slow?

[agd5f]

And what are major differences between DPM and PowerPlay on purely technical layer? I.e. are they anyhow different in terms of voltage/freq scaling, etc from practical standpoint?

No major differences. Same clocks and voltages uses in both cases. The main difference is the programming sequences and the interactions with other modules (e.g., displays, multi-media, etc.).

[agd5f]

@agd5f

Why is Fiji still so extremely slow?

I think there is an issue with some boards. The boards we've been using and other testers have reported show much better performance.