Swappiness settings and perfomance

Mixhel · 2011-02-07 10:16:18

Hey guys. How is everyone?
well I want make this topic about tunning swap and ram using swappiness and vm.vfs_cache_pressure. I was testing those comands and their values... I found a interesting thing....

most of tutorials about vm.swappiness=20 are obsolete? I mean out-of-update...

Why?

Well today I was testing those values of swappiness and after a time of changing values for swappiness... I finished. And when I finished it i found that value 100 is better than low values in system with 2 gb or more and this value still after 5 hours still didn't use swap only ram... and when i was looking in kinfocenter on KDE I saw that box where is cache disk says more cache disk and less memory free means great perfomance.. ( well in spanish says it if someone can translate or put what said on english is welcome haha! )

respect to vm.vfs_cache_pressure the value 50 works fine... now my system with v.swappiness=100 and vm.vfs_cache_pressure=50 loads very fast everything ahh and almost i forget... I had compress /usr with aufs ( https://wiki.archlinux.org/index.php/Ma … erformance )

Well I can confirm for now that I choose those values on a Laptop and desk and works very faster after of compress /usr and maybe too works without compress it...
because in Laptop works fast and desk too but desktop hadn't compress /usr

Can someone test it with 1gb 2 or more gb and see some performance improvement with those values?
vm.swappiness=100
vm.vfs_cache_pressure=50

Some programs who I see speed up open:

Gimp ( Laptop )
Inkscape ( Laptop)
Libreoffice ( Loads database heavy fastest) ( on desk before of tweaks took a bit load it after this load almost instantly ) ( on laptop the presentations loads faster too after tweak)
Opera ( both )
When KDE starts ( I see more speed on Desk of course a fast cpu but in Laptop too )

Hardware:
laptop:
cpu: Turion ii X2 p520
Ram: 3 gb
Desktop:
cpu: phenom ii x6
Ram: 8 gb

Their hd are of 5200 rpm and with hdparm test almost their timing buffered disk reads are Laptop: 90-96 mb/s range and desk still I don't test

Regards!

PD: sorry for my English I'm working hard for learn it

Post your experiences with those settings !!

Last edited by Mixhel (2011-02-07 10:37:35)

litemotiv · 2011-02-07 10:21:18

Moved to Kernel & Hardware.

Mixhel, could you please edit your topic title so that it reflects better what you are trying to achieve?

Army · 2011-02-07 12:54:59

I have a laptop with 512mb ram and I've been using vm.swappiness=100 and vm.vfs_cache_pressure=50 for quite some time and it's really better than the standard setting and certainly better than swappiness = 0 or stuff like that.

Do you also use vm.dirty_ratio = 10 and vm.dirty_background_ratio = 5 ? I found those values on a blog some time ago and all in all it seemed to be a very good setting.

pataphysician · 2011-02-07 13:06:08

If you have swappiness set to 100 and you have no swap used, then your typical computer usage in combination with your available memory is unlikey to ever use swap, therefor your swappiness value will probably be irrelevant to performance.

Mixhel · 2011-02-07 16:21:35

pataphysician wrote:

If you have swappiness set to 100 and you have no swap used, then your typical computer usage in combination with your available memory is unlikey to ever use swap, therefor your swappiness value will probably be irrelevant to performance.

laptop and desk have swap and under big files sizes never used swap partition and yes I have swap partition for desk is 5 gb and for laptop is 3 gb and watched in console for 4 hours when i was working moving heavy files or copy that for watch swap use... and the max was 200 mb for laptop and 0 for desk

Mixhel · 2011-02-07 16:30:31

Army wrote:

I have a laptop with 512mb ram and I've been using vm.swappiness=100 and vm.vfs_cache_pressure=50 for quite some time and it's really better than the standard setting and certainly better than swappiness = 0 or stuff like that.
Do you also use vm.dirty_ratio = 10 and vm.dirty_background_ratio = 5 ? I found those values on a blog some time ago and all in all it seemed to be a very good setting.

the value 10 is the default O:
i will test with 5

Arch Linux

#1 2011-02-07 10:16:18

Swappiness settings and perfomance

#2 2011-02-07 10:21:18

Re: Swappiness settings and perfomance

#3 2011-02-07 12:54:59

Re: Swappiness settings and perfomance

#4 2011-02-07 13:06:08

Re: Swappiness settings and perfomance

#5 2011-02-07 16:21:35

Re: Swappiness settings and perfomance

#6 2011-02-07 16:30:31

Re: Swappiness settings and perfomance

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