Arch Linux

technolog

Member

From: Europe / Slovenia / Grosuplje

Registered: 2012-01-28

Posts: 117

Despite having GCC with nice = 19, the system still lags

As the title says, I'm compiling some software in the background. I have set all processes to nice=19 and I have checked in the system monitor that is indeed the case (all top cpu processes have nice = 19).

But then the chromium or intellij or any other application for that matter still lags a lot and presents sluggish behavior. Even if I set their nice level to -20.

Why is that?

Last edited by technolog (2015-03-30 16:26:33)

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,794

Re: Despite having GCC with nice = 19, the system still lags

Out of physical memory?  Is the disk drive thrashing?

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mychris

Member

From: Munich

Registered: 2012-09-15

Posts: 68

Re: Despite having GCC with nice = 19, the system still lags

CPU scheduler? I/O scheduler? Which one do you use?

https://www.kernel.org/doc/Documentatio … design.txt

technolog

Member

From: Europe / Slovenia / Grosuplje

Registered: 2012-01-28

Posts: 117

Re: Despite having GCC with nice = 19, the system still lags

I'm not out of memory.

I/O scheduler shouldn't matter (it's CFQ), CPU scheduler is the default, I did not change anything from default Arch install.

It's not that I am unable to work, but everything feels really sluggish. A lot more than usual.

Last edited by technolog (2015-03-30 16:46:36)

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,597

Website

Re: Despite having GCC with nice = 19, the system still lags

If not memory consumption then this is where bfs excels.. Try the linux-ck kernel from the AUR or from my repo and report back.

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CPU-optimized Linux-ck packages @ Repo-ck  • AUR packages • Zsh and other configs

Alad

Wiki Admin/IRC Op

From: Bagelstan

Registered: 2014-05-04

Posts: 2,412

Website

Re: Despite having GCC with nice = 19, the system still lags

Maybe you should tell us what package you're compiling and set options in /etc/makepkg.conf . Or details on your hardware for that matter.

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technolog

Member

From: Europe / Slovenia / Grosuplje

Registered: 2012-01-28

Posts: 117

Re: Despite having GCC with nice = 19, the system still lags

I am compiling chromium with ozone (-O3, -march=native). All compiler processes have nice = 19.

I have run scala compiler which normally takes around 10s for this program, but now it took just under half a minute.

I guess I'll check out linux-ck as suggested.

Soukyuu

Member

Registered: 2014-04-08

Posts: 854

Re: Despite having GCC with nice = 19, the system still lags

I'm compiling software often as well, and the system has been very responsive even at spikes of 100% on all of my 4 cores. I am using linux-ck, so maybe it's that, as others suggested. I've been very pleased with the overall performance of the -ck kernel so far, the only issue I ever had were random kernel panics with the BFQ scheduler enabled for my SSD... (I always confuse BFS and BFQ, the BFQ is the disk scheduler, right?)

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[ Arch x86_64 | linux | Framework 13 | AMD Ryzen™ 5 7640U | 32GB RAM | KDE Plasma Wayland ]

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,597

Website

Re: Despite having GCC with nice = 19, the system still lags

Yes, BFQ is the IO scheduler while BFS is the CPUS scheduler.  BFQ is optional while BFS is enabled by default in linux-ck.

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CPU-optimized Linux-ck packages @ Repo-ck  • AUR packages • Zsh and other configs