maemo.org - Talk - How to set swappiness?

maemo.org - Talk (https://talk.maemo.org/index.php)

- Maemo 5 / Fremantle (https://talk.maemo.org/forumdisplay.php?f=40)

- - How to set swappiness? (https://talk.maemo.org/showthread.php?t=48966)

Re: How to set swappiness?

Quote:

Originally Posted by allnameswereout (Post 816855)

Have you noticed a decrease of screen tearing?

With these new values? Yes, absolutely.

It's difficult to substantiate with benchmarks but the main effect is on the gui snappiness, swiftness, lack of tearing, in a word fluidity. I didn't imagine that those problems depended on memory allocation in ram vs flash memory.

Re: How to set swappiness?

Quote:

Originally Posted by allnameswereout (Post 815391)

Ehm...

:confused:

No need for fugly sysvinit junk.

On Maemo 5 just put in /etc/event.d/tuning

Code:

description "N900 tuning"

author "VA"



console output



start on started rcS-late



script

       echo "30" > /proc/sys/vm/swappiness

       echo "0" > /proc/sys/vm/page-cluster

       echo "1" > /proc/sys/vm/laptop_mode

       echo "1" > /proc/sys/vm/oom_kill_allocating_task

       echo "0" > /proc/sys/vm/dirty_expire_centisecs

       echo "0" > /proc/sys/vm/dirty_writeback_centisecs

       echo "60" > /proc/sys/vm/dirty_background_ratio

       echo "95" > /proc/sys/vm/dirty_ratio

       echo "0" > /proc/sys/net/ipv4/tcp_timestamps

       echo "1" > /proc/sys/net/ipv4/tcp_no_metrics_save

end script

For explanation of each of these settings see URL in my previous post.

Holy crap.

On my device, this is a *significant* change. I used to get all these hangs and "hello, is anybody home?" and "Hey, I *CLICKED* here already" frustrated interaction with the device. With these changes, they all went away (so far - *knock on wood*).

I must say it was an enlightening read about the swap stuff in that linux thread. Clearly, in my opinon, swappiness=100 is *always* utter madness on *any* system.

The example mentioned in that thread is when un-tar'ing a multi-megabyte file, the filecache utilizing all "free" space as disk-cache, hence swapping out all apps, hence making the machine dead slow. Well, that's crazy, an un-tar basicaly serially reads/writes ONCE, and needs NO CACHEING AT ALL for efficiency!!!

Thank you deepest for the person inventing these settings. For now, I label them golden. The only thing that could un-golden these settings would be crash issues (none so far) or battery drainage (not enough data yet to judge, but it is very unlikely, if anything avoiding swapping should take LESS battery than excessive swapping would!)

Again, thanks

/Z

Re: How to set swappiness?

Not to be too dramatic, but if you're not noticing an improvement from swappiness = 30, you might want to audit what you have running and/or installed. With almost 5 days of uptime, and with no other changes to usage patterns, my n900 consistently feels like a different device. And I log many hours a day with it.

Hopefully in the next few weeks I'll try some of the other optimizations, but this one seems like a no-brainer.

Also, about 2 months ago I made the following recommended changes in:

/home/user/.config/tracker/tracker.cfg

Code:

...

LowMemoryMode=true

...

Throttle=15

...

This too had a positive effect on performance, but don't forget to restart the tracker.

Re: How to set swappiness?

Just warning - N900 has not enough RAM for all applications which it runs, typical sizes are:

gstreamer - 100MB,
pulseaudio - 60-70MB
modest - 45-80MB
browser - 60-120MB or more
etc

And it also has a slow flash for swap.

So, with very non-aggressive swapiness it is easy to hit a situation then you have no free memory and incoming call may wait until kernel swaps out some apps. It may take up to 5-10 secs just to swap out... but kernel may need to swap in/load a phone application... ===> missed call.

I believe it is a reason why Nokia set swapiness to 100.

Re: How to set swappiness?

Well, we're on the bleeding edge here, maybe it's time for a dynamic strategy that involves mlock type mechanisms.

Re: How to set swappiness?

I've been running with swappiness set at 30 for about a week now and have noticed a tremendous improvement in speed and battery life. I'm trying now with allnameswereout's further tuning to see how it improves.

egoshin's point makes sense; i hardly ever get calls so haven't noticed any such problem, but would be interested in hearing about others' experience.

Re: How to set swappiness?

im currently using 30 swappiness and 0 page cluster.

heres an experiment i did: opened about 15 or more odd applications, including the media player, phone, conversations, pictures, microb etc. then i tried calling my phone from a landline a couple of times and it did what it was expected to do. no lags in receiving calls what so ever. there was tearing tho when i was scrolling the screen and i can feel that the system was working really hard..

ill try to observe a few more days if theres anything unusual happening but a couple of days ago when i only tried the 30 swappiness setting, the conversations application became laggy when its coming from sleep. ill check if this will happen again with my page cluster set to 0.

Re: How to set swappiness?

Quote:

Originally Posted by elbttrd (Post 817277)

i did the exact same thing!!! lol

using the tuning script from knownokias page. it did seem to lag ALOT though wen i updated filebox thru application manager, and it took about 16seconds for the phone to receive the call :S will test again

edit: it seems so. apt-worker lags up the phone once i install something. its prob not getting enough swap for setting up the apps, only way is to kill it from xterm

Re: How to set swappiness?

made the same experience with apt-worker some days ago. swappiness was set to 30 without further modified settings.

Re: How to set swappiness?

Shall I remove faster kinetic scrolling - (desktop_kinetic_2.2.138-1+0m5_armel.deb)
before installation of this add-on?
Sorry if my question looks noob...

Thanks.
Regards