AMD and Valve Working On New Linux CPU Performance Scaling Design

Along with other optimizations to benefit the Steam Deck, AMD and Valve have been jointly working on CPU frequency/power scaling improvements to enhance the Steam Play gaming experience on modern AMD platforms running Linux. Phoronix reports: It's no secret that the ACPI CPUFreq driver code has at times been less than ideal on recent AMD processors with delivering less than expected performance/behavior with being slow to ramp up to a higher performance state or otherwise coming up short of disabling the power management functionality outright. AMD hasn't traditionally worked on the Linux CPU frequency scaling code as much as Intel does to their P-State scaling driver and other areas of power management at large. AMD is ramping up efforts in these areas including around the Linux scheduler given their recent hiring spree while it now looks like thanks to the Steam Deck there is renewed interest in better optimizing the CPU frequency scaling under Linux.

AMD and Valve have been working to improve the performance/power efficiency for modern AMD platforms running on Steam Play (Proton / Wine) and have spearheaded "[The ACPI CPUFreq driver] was not very performance/power efficiency for modern AMD platforms...a new CPU performance scaling design for AMD platform which has better performance per watt scaling on such as 3D game like Horizon Zero Dawn with VKD3D-Proton on Steam." AMD will be presenting more about this effort next month at XDC. It's quite possible this new effort is focused on ACPI CPPC support with the previously proposed AMD_CPUFreq. Back when Zen 2 launched in 2019, AMD did post patches for their new CPUFreq driver that leveraged ACPI Collaborative Processor Performance Controls but the driver was never mainlined nor any further iterations of the patches posted. When inquiring about that work a few times since then, AMD has always said it's been basically due to resource constraints that it wasn't a focus at that time. Upstream kernel developers also voiced their preference to seeing AMD work to improve the generic ACPI CPPC CPUFreq driver code rather than having another vendor-specific solution. It's also possible AMD has been working on better improvements around the now-default Schedutil governor for scheduler utilization data in making CPU frequency scaling decisions.

C'mon AMD

[bill_mcgonigle]

I like how a game company has to tell a CPU company how it should write CPU drivers. AMD needs to fund their linux team - they appear to be really overloaded and underresourced. AMD - send patches and push them upstream ASAP so people can actually give you money for hardware.

Thanks Valve, for making things better for everybody.

Re:

[ToasterMonkey]

I like how a game company has to tell a CPU company how it should write CPU drivers. AMD needs to fund their linux team - they appear to be really overloaded and underresourced. AMD - send patches and push them upstream ASAP so people can actually give you money for hardware.

Thanks Valve, for making things better for everybody.

Well come on, if it weren't for games, where would desktop PC hardware be right now, really.

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[rtb61]

Games, nahh. The ultimate accessory for big screen TVs, plug a dongle into a not so smart TV ad https://www.steamdeck.com/en/ [steamdeck.com] and you done. All the controls you need and the console display on the big screen, just plug console into power point vis usb (a tether to keep it wandering) and stream or browse or https://www.libreoffice.org/ [libreoffice.org] what ever, ohh and you can play games.

Get Linux running on your big screen TV with a dongle, all in the console, nothing to do but plug in dongle and FOSS world there, and you

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[thegarbz]

I like how a game company has to tell a CPU company how it should write CPU drivers.

No they don't. A customer with money needs to tell a vendor to focus on the needs of the customer in a bracket they have been previously ignoring because of how irrelevant that market segment was.

This was up until the Steam Deck was announced a completely non-existent market segment.
- AMD makes up 30% market share on desktop, but only a fraction of that on Laptop.
- Steam survey shows 1% market share for Linux where Steam is installed (may or may not mean gaming, and also duplicate counts people who install

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[raymorris]

> Same logical fallacy as with Mozilla/Phoenix/Firefox back in the IE5 days ...
> to the best of what I can think of, surprisingly, the attractivity of the Firefox fox logo ... that changed things around.

Marketing, including a two-page ad in the New York Times, was half of what separated Firefox from Mozilla.

https://blog.mozilla.org/press... [mozilla.org]

Mozilla was a suite - browser, email, and composer; and was code-focused. The Firefox project was switching the focus to marketing just a browser. With market shar

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[thegarbz]

Same logical fallacy as with Mozilla/Phoenix/Firefox back in the IE5 days:

Developers: We will not focus on supporting Firefox until it gets a bigger market share.
Users: We will not install Firefox until it gets support by more sites.

That's not a logical fallacy. In fact it's quite logical for all involved and underpinned by well researched economic principles.

AMD doesn't exist for the purposes of supporting some OS or pushing someone else's agenda. They exist to make money. Dedicating resources into where its customers are isn't a fallacy, it's good common business sense. AMD's actions exist to benefit AMD, not some non-existent Linux customers.

Valve does the right thing right now.

Valve is doing nothing other than the actions which directly benefit Valve. They are investi

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[drinkypoo]

Combine all that and there's very little incentive to actually setup develop a driver to boost performance per watt on a platform that no one uses.

Ultimately there's only one reason AMD didn't bother, it didn't affect sales. I know that I buy AMD even though they have shit PM compared to Intel (IME, on any OS) because of other factors. If all else were equal I'd pick Intel just to get working PM, but it isn't so I don't and consequently I'm part of the problem. However, I'm a minuscule part compared to companies choosing AMD systems, which has only increased over the years as Intel has willfully or incompetently continued to drop the ball on security.

Makes sense

[thegarbz]

When Zen 2 was released AMD's power management became more advanced than any OS's default driver was capable of handling. The difference is with nearly all gaming happening on Windows there was a push to release a tweaked windows power management driver nice and early.

With most gaming not happening on mobile devices (no need for aggressive power management) and Linux having a 1% market share, and AMD having a tiny mobile market share to date, there really hasn't been much of a point in optimising this until now.

Valve sold out of it's 110000 Steam Decks within 90 minutes. I suspect this device will see a big skew in the statistics for OSes with AMD on mobile platform, and for Linux gaming.