AMD Core Performance Boost For Linux Getting Per-CPU Core Controls (phoronix.com) 8
An anonymous reader shared this report from Phoronix:
For the past several months AMD Linux engineers have been working on AMD Core Performance Boost support for their P-State CPU frequency scaling driver. The ninth iteration of these patches were posted on Monday and besides the global enabling/disabling support for Core Performance Boost, it's now possible to selectively toggle the feature on a per-CPU core basis...
The new interface is under /sys/devices/system/cpu/cpuX/cpufreq/amd_pstate_boost_cpb for each CPU core. Thus users can tune whether particular CPU cores are boosted above the base frequency.
The new interface is under /sys/devices/system/cpu/cpuX/cpufreq/amd_pstate_boost_cpb for each CPU core. Thus users can tune whether particular CPU cores are boosted above the base frequency.
Is this something for non-embedded usage? (Score:5, Insightful)
Re: (Score:2)
For desktop, probably not common.
For data centers and any programs that are timing critical on predictability to where CPU frequency changing on the fly causes havoc, I could see why.
Re: (Score:2)
Re:Is this something for non-embedded usage? (Score:4, Interesting)
I can see a few desktop use cases. Games for example. And before you laugh, there are patches in Linux that emulate the Windows NT synchronization primitives to increase WINE/Proton performance.
Given modern CPUs have a number of efficiency and performance cores, performance critical threads will want to attach themselves to a P-core while less critical threads can E-cores. And if you know your came well enough, there are plenty still using single-threaded game loops, so having them on a P-core that can go into turbo boost is certainly helpful.
There are probably useful cases for servers as well, but desktops I would think gaming would be the big one. And I suspect the likes of the Steam Deck are pushing AMD to increase Linux performance.
Re: (Score:2)
I am not an expert on this topic.
Over in Windows land, the thread scheduler decides which threads get handed off the to the performance cores, which ones end up on the efficient cores, and another service that decides when to ask the CPU for more performance. Software that understands Hybrid CPU QOS can indicate a preference for P or E cores, but most software doesn't so the thread scheduler makes educated guesses.
There's a bunch of interesting under the hood stuff here with P cores, E cores, variable cloc
Re: (Score:1)
In order to make proper use of this, I guess you would want to set CPU-affinity per process (or for a specific interrupt), balance it, and increase (or decrease) the core frequency. I wonder if there is any desktop case for such precision control.
In that case I would wonder on the power requirement.