You will want to force your CPU into high performance mode for Vulkan games on Linux

Hmm, does this setting the CPU governor to performance impact games otherwise you think (like, with OpenGL on a weak CPU?).

I have a AMD quadcore A8-6410 ("up to 2.4 ghz) on my laptop, and I struggle to play Shadow Tactics (and other unity games) on lowest settings, sometimes I think my CPU is at fault as much as my GPU. top reports around 250% CPU usage (which means 2.5 cores used I guess) for Shadow Tactics. Is it possible to increase that usage, you think?

Hmm, does this setting the CPU governor to performance impact games otherwise you think (like, with OpenGL on a weak CPU?).

It's not magic, it doesn't suddenly make a weak CPU any better. It's only an issue if when playing games your CPU isn't being set into high performance mode. With OpenGL games it likely always is, since they are generally heavy on the CPU.

Hmm, does this setting the CPU governor to performance impact games otherwise you think (like, with OpenGL on a weak CPU?).

I have a AMD quadcore A8-6410 ("up to 2.4 ghz) on my laptop, and I struggle to play Shadow Tactics (and other unity games) on lowest settings, sometimes I think my CPU is at fault as much as my GPU. top reports around 250% CPU usage (which means 2.5 cores used I guess) for Shadow Tactics. Is it possible to increase that usage, you think?

It's worth a try. I had to do it - strange enough - for Limbo to work in the correct speed. :)

Will try this later today on dota and serious Sam with a strong cpu (6600k) and see how it affects performance.

I always set the governor in performance mode when I'm playing, this is not the only game with such issues.
While my current Intel CPU is not that affected, the former AMD one FX 8370 was really bad at this, the framerate was all over the place on ondemand mode and stuttering all the time.

@liamdawe
Uh, powersave isn't the default governor, at least it shouldn't be. powersave will run your CPU at the minimum freq.
You want ondemand.


https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt


Last edited by poisond on 23 Mar 2017 at 10:32 am UTC

Thanks for the heads up, Liam. I made two files, called gov_perf and gov_psav and copied the short scripts into them, then made them executable and copied them to usr/bin. That way I can issue the commands from any directory with a single word typed. I'm sure I could add gov_perf to launcher scripts of games so that the process is auto-magic. Now to figure out a way to make games trigger gov_psav upon exit... 


Last edited by Keyrock on 23 Mar 2017 at 10:35 am UTC

@liamdawe
Uh, powersave isn't the default governor, at least it shouldn't be. powersave will run your CPU at the minimum freq.
You want ondemand.


https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt

It is for Intel (with intel_pstate), ondemand is the default for AMD.

@liamdawe
Uh, powersave isn't the default governor, at least it shouldn't be. powersave will run your CPU at the minimum freq.
You want ondemand.


https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt

Not exactly. AMD chips use ondemand, as well as some really old Intel chips. Newer Intel chips use powersave as the intel_pstate driver takes care of the scaling.

Edit: Ninja'd


Last edited by Keyrock on 23 Mar 2017 at 10:40 am UTC

@liamdawe
Uh, powersave isn't the default governor, at least it shouldn't be. powersave will run your CPU at the minimum freq.
You want ondemand.


https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt

Well, to be sure I've updated the text to mention people to use either, thanks for the extra tip.

@liamdawe
Uh, powersave isn't the default governor, at least it shouldn't be. powersave will run your CPU at the minimum freq.
You want ondemand.


https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt

I'm not 100% sure, but AFAIK, I found powersave and performance the only states implemented for my i3570K when I looked.

*edit*
http://www.phoronix.com/scan.php?page=news_item&px=MTM3NDQ
The reality is that such control algorithms are CPU specific, the notion of a generic "for all cpus" governors is just outright flawed; hardware behavior is key to the algorithm in the first place....


Last edited by Eike on 23 Mar 2017 at 10:45 am UTC

Uh? "powersave" shouldn't be the default. I think "interactive" is. It provides some sane balance between power usage and performance.

I would generally advise "powersave" only when battery life is a problem, to maximize its capacity (and bear with a bit of stuttering/other), maybe lower the settings a bit as well to minimize the power draw.

Now, on desktop, I think that "interactive" is the default, which is a good one IMO. I would be curious to see some comparison with "performance" on Vulkan, but I don't expect it to change the result by more than 0.5-1%, and you might have much higher idle power draw. I personally never bother to change it.

You might also want to avoid "conservative", which might have lower performance than "powersave".

That's if for the basic performance governors, but I want to point out that, while performance governors and schedulers might seem "dumb" (probably because they are well-documented, and generally don't try the one-size-fits-all approach), they are well-proven and battle tested, from small embedded devices, to Android phones, to supercomputers.

There is also more to scheduling than performance governors, and the schedulers can have a role to play as well, but I don't think that gaming is the most complex scenario to handle, so this should make little difference, except for special cases.

EDIT: Ninja'd by a bunch of people :P Also, it seems that I am confusing "ondemand" and "interactive". I can't check ATM that "interactive" is what I am using, but IIRC, it should be a bit more aggressive on frequencies than "ondemand". Not that much difference, though. And yeah, "ondemand" might be the default.


Last edited by MayeulC on 23 Mar 2017 at 10:49 am UTC

Uh? "powersave" shouldn't be the default. I think "interactive" is. It provides some sane balance between power usage and performance.

I would generally advise "powersave" only when battery life is a problem, to maximize its capacity (and bear with a bit of stuttering/other), maybe lower the settings a bit as well to minimize the power draw.

Now, on desktop, I think that "interactive" is the default, which is a good one IMO. I would be curious to see some comparison with "performance" on Vulkan, but I don't expect it to change the result by more than 0.5-1%, and you might have much higher idle power draw. I personally never bother to change it.

You might also want to avoid "conservative", which might have lower performance than "powersave".

That's if for the basic performance governors, but I want to point out that, while performance governors and schedulers might seem "dumb" (probably because they are well-documented, and generally don't try the one-size-fits-all approach), they are well-proven and battle tested, from small embedded devices, to Android phones, to supercomputers.

There is also more to scheduling than performance governors, and the schedulers can have a role to play as well, but I don't think that gaming is the most complex scenario to handle, so this should make little difference, except for special cases.

My Manjaro system doesn't even have an interactive governor

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
performance powersave

I've updated to link to the Arch Wiki for the resetting bit, according to the Wiki:

Depending on the scaling driver, one of these governors will be loaded by default:
ondemand for AMD and older Intel CPU.
powersave for Intel CPUs using the intel_pstate driver (Sandy Bridge and newer).

i have always used my keyboard macro buttons for forcing ondemand or performance. even with opengl it helped with the microstutering

my script is like that:

pkexec cpupower frequency-set -g performance && notify-send "Performance Mode" "Cpu clocks set to perfromance mode" -t 2000 -i messagebox_info

and other one for the ondemand mode also. pkexec is for polkit rule to not have to use root.

...

My Manjaro system doesn't even have an interactive governor

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
performance powersave

Yeah, I remembered reading the other posts that it might not be standard. I don't have my computer with me ATM, unfortunately, so I can't check, but I will do in a couple hours.
"interactive" seems to be more of a real time governor, it looks more common on Android.

What I said is generally valid about "ondemand", though it ramps up a bit slower.

My bad, here I was thinking defaults were a bit less fragmented all over the place. Hey, that's part of the Linux charm, no? :D

Thanks for the heads up, Liam. I made two files, called gov_perf and gov_psav and copied the short scripts into them, then made them executable and copied them to usr/bin. That way I can issue the commands from any directory with a single word typed. I'm sure I could add gov_perf to launcher scripts of games so that the process is auto-magic. Now to figure out a way to make games trigger gov_psav upon exit... 

Maybe setting the following Steam game launch config works...

kdesu gov_perf ; %command% ; kdesu gov_psav 

(You can use whatever method you like to get privileges. kdesu is just an example)

I would give a try to schedutil (https://wiki.archlinux.org/index.php/CPU_frequency_scaling)

there is any way to delay an command to run only when the last command finish?


add an non steam game (it is an steam game, but do it anyway)
echo performance | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ;
command to launch the game ;
echo powersave | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

not tested!

For a more easy way to change the settings, install the package "indicator-cpufreq"("sudo apt install indicator-cpufreq" for those of you in Ubuntu). It will show a icon in your taskbar were with 2 mouse clicks you can change to the Performance governor and back. I use it for both AMD and Intel CPUs for years and it works great, for any DE.