Linux 5.3 Picks Up Utilization Clamping - Ensuring GUI Threads Get Maximum Frequency

[phoronix]

Phoronix: Linux 5.3 Picks Up Utilization Clamping - Ensuring GUI Threads Get Maximum Frequency

The scheduler changes for the Linux 5.3 kernel are as busy as ever...

http://www.phoronix.com/scan.php?page=news_item&px=Linux-5.3-Scheduler-Clamping

[TheOne]

Wonder if this will help in games performance...

[Guest]

Interesting. Looks like this is more for mobile devices (mainly Android).

[jacob]

It's not entirely clear to me if this is for big.little-style configurations where it keeps the GUI threads on the "big" cores, or if it will also be useful on laptops, e.g. to pin GUI threads to cores that will not have their frequency reduced?

[Linuxxx]

Wonder if this will help in games performance...

If anyone is interested in getting the absolute best gaming performance & lowest-latency/smoothest frame-rate out of their Linux machines right now (especially with activated mitigations), here is what You can do:

- If not already, switch to Arch Linux (or Manjaro) and enable the "repo-ck" repository to install a MUQSS-enabled Linux Kernel tailored to your CPU architecture.

- Install Feral's GameMode & Lutris (for easy activation).

- In your 'gamemode.ini' add:

softrealtime=on

- Now, when starting your games with GameMode, your CPU governor is already being set to 'performance'; however, if you are on Intel, be sure to also set the "perf-bias" knob to '0' (zero) for maximum performance preference.

- Also, if running nVidia's binary driver, enable Triple-Buffering by default in your Xorg.conf like this under the "device" section:

Option "TripleBuffer" "1"

- Just in case, make also sure that the IRQs are distributed across all your CPU cores by starting the "irqbalance" daemon on start-up.

These are the most important settings that come to my mind right now.
With the above tweaks, even a Linux machine from the Core2-era had never performed this good in its 11-year lifespan!

If anyone has any more ideas to tweak a Linux system for optimal gaming performance or latency-sensitive applications in general, be sure to share!

[starshipeleven]

It's not entirely clear to me if this is for big.little-style configurations where it keeps the GUI threads on the "big" cores, or if it will also be useful on laptops, e.g. to pin GUI threads to cores that will not have their frequency reduced?

it will be useful everywhere you are running a GUI and want to do any amount of multitask, It's about time that Linux starts to pick up some optimizations for desktop or end-user devices.

[andreano]

I have wanted a CPU scheduler that runs "nice" tasks at low clockspeed.

Currently, you have to pin them to specific cores and set the powersave governor on those cores - all cores in my case - to achieve that, which is totally inflexible: The frequency is fixed at the bottom even when foreground tasks take precedence, so I need to temporarily switch scheduler manually.

[Linuxxx]

it will be useful everywhere you are running a GUI and want to do any amount of multitask, It's about time that Linux starts to pick up some optimizations for desktop or end-user devices.

Actually, the culprit here really seems to be Linux's default CPU scheduler (CFS).
Just by switching over to Linux-ck with its MUQSS CPU scheduler, one can notice noticably improved smoothness just about everywhere!
Bonus points if one also switches over to the performance governor on boot & installs the Linux-ck kernel optimized for the available CPU topology.
And for anyone concerned about the CPU running hot: No, as it will be idling in its deepest sleep state anyway most of the time.
(Easily checkable by running):

sudo cpupower monitor

BTW, anyone using openSUSE Tumbleweed (like I did previously) should expect worse multi-tasking behavior since Linux 5.0, since some genius decided it would be a good idea to disable kernel-preemption (PREEMPT), thus robbing from the Linux kernel the soft real-time advantage, and just to top it all off, all of that without even mentioning it anywhere!

[jacob]

it will be useful everywhere you are running a GUI and want to do any amount of multitask, It's about time that Linux starts to pick up some optimizations for desktop or end-user devices.

That's definitely true, although to be fair, I think that Linux's desktop weaknesses are not really due to the kernel but rather to the lower layers of the standard userland environment with their unixy baggage. Wayland and systemd are making strides to improve the situation but there are still miles to go.

[Linuxxx]

That's definitely true, although to be fair, I think that Linux's desktop weaknesses are not really due to the kernel but rather to the lower layers of the standard userland environment with their unixy baggage. Wayland and systemd are making strides to improve the situation but there are still miles to go.

Have you ever even tried any other Linux kernel than the one that comes with your distro of choice?
If not, how do you come to the conclusion that the default Linux kernel configuration with the 'Completely Fair Scheduler' isn't to blame here?
If you haven't tried Linux-ck yet, trust me, you're missing out...