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maemo.org - Talk (https://talk.maemo.org/index.php)
-   Nokia N900 (https://talk.maemo.org/forumdisplay.php?f=44)
-   -   N900, ohmd, syspart, VM & swap tweaks (https://talk.maemo.org/showthread.php?t=71115)

Tigerite 2011-05-31 14:24
Re: N900, ohmd, syspart, VM & swap tweaks
 
Has anyone ever tried the deadline scheduler and:

Code:
echo 1 > /sys/block/mmcblkX/queue/iosched/fifo_batch
? I've just compiled BFS with the config option enabled, and will be giving it a try over the next few days. I got the idea from here

hawaii 2011-06-01 04:01
Re: N900, ohmd, syspart, VM & swap tweaks
 
I'd also like to try the anticipatory scheduler, a lot of the Android guys have been switching over to it...

Tigerite 2011-06-01 08:33
Re: N900, ohmd, syspart, VM & swap tweaks
 
I considered anticipatory, but it was taken out of the kernel altogether as of 2.6.33 and supposedly CFQ replaced it after 2.6.18. Also I'm never sure whether heuristics are a good idea or not.. I suppose it wouldn't hurt to add it to the config as a module, though.

Tigerite 2011-06-01 11:04
Re: N900, ohmd, syspart, VM & swap tweaks
 
Ok, I've built the latest BFS from git tree, with both deadline and anticipatory enabled as modules within the config. Everything runs as smoothly as before, with no added overhead. To enable either one of them, you have to echo deadline or anticipatory to /sys/block/mmcblk0/queue/scheduler - this seems to automagically insert the corresponding module (probably best to rmmod if you then change back to noop or cfq at a later date, though, as they stay loaded). I did find a thread regarding anticipatory on Android and found this snippet to be quite interesting:

Quote:
For instance anticipatory scheduler focuses on contiunous read and avoiding head movement which is not the case for flash drives.

Completely different rules apply here.

The community (Linux SSD) recommends NOOP or DEADLINE schedulers, I prefered DEADLINE for it's focus on preventing read starvation.
It works the best (elevator = deadline) for my Asus EEE PC 901 with SSD drives and attached SD cards.
Writes are slower, but there's much less lag when browsing web or opening folders because "read" operations have priority.
The same seems to work on my Galaxy S with stock JM1 with or without one-click-lag-fix.
..which makes me think deadline might be the best scheduler to use, even though the N900's drive isn't exactly an SSD?

MONVMENTVM 2011-06-01 18:16
Re: N900, ohmd, syspart, VM & swap tweaks
 
Quote:
Originally Posted by Tigerite (Post 1020062)
Ok, I've built the latest BFS from git tree, with both deadline and anticipatory enabled as modules within the config. Everything runs as smoothly as before, with no added overhead. To enable either one of them, you have to echo deadline or anticipatory to /sys/block/mmcblk0/queue/scheduler - this seems to automagically insert the corresponding module (probably best to rmmod if you then change back to noop or cfq at a later date, though, as they stay loaded). I did find a thread regarding anticipatory on Android and found this snippet to be quite interesting:



..which makes me think deadline might be the best scheduler to use, even though the N900's drive isn't exactly an SSD?
Probably because most processes hang on read operations. Giving them higher priority should speed things up for normal usage. So I think when you're downloading something and at the same time are trying to start an app etc. the device should be snappier, while you couldn't care less about the download.

joerg_rw 2011-06-19 22:53
Re: N900, ohmd, syspart, VM & swap tweaks
 
Quote:
Originally Posted by vi_ (Post 969197)
Holy WALL OF TEXT bro. Please, some formatting!
HOLY, and you fullquote it, to add that one liner comment :-S
/j

F2thaK 2011-06-19 23:46
Re: N900, ohmd, syspart, VM & swap tweaks
 
Quote:
Originally Posted by jurop88 (Post 969193)
Everything said, here follows a resume of my experiences so far.
...
Thanks, just applied all your settings. See how things go. :D

pigeond 2012-03-14 02:03
Re: N900, ohmd, syspart, VM & swap tweaks
 
Hi all,

I've also been trying to tweak /usr/share/policy/etc/current/syspart.conf

One thing I noticed though is, sometimes the values are being applied for a little while, and then it gets overridden again by ohmd.

For example, I've tried changing the desktop cpu-shares to say 4096, then i run "stop ohmd" and "start ohmd". For a short time, I can see the value 4096 is being set by cat-ing the corresponding value in /syspart/desktop/cpu.shares

But then after a while, ohmd seems to write back the original value 6144 to it.

Any ideas?

Thanks.

jurop88 2012-03-14 07:21
Re: N900, ohmd, syspart, VM & swap tweaks
 
Now I don't remember exactly - I worked on that a long ago - but there is a policy file written and compiled in Prolog (?) somewhere read by ohmd - and it's responsible for that.
Long story short, what I remember is that I resigned after a lot of searching. Now I am really short on time for next month, but if you are interested in looking at that I can look for my knowledge and send everything to you - some material found on wikis, irc logs and the like

freemangordon 2012-03-14 08:02
Re: N900, ohmd, syspart, VM & swap tweaks
 
Quote:
Originally Posted by jurop88 (Post 1179219)
Now I don't remember exactly - I worked on that a long ago - but there is a policy file written and compiled in Prolog (?) somewhere read by ohmd - and it's responsible for that.
Long story short, what I remember is that I resigned after a lot of searching. Now I am really short on time for next month, but if you are interested in looking at that I can look for my knowledge and send everything to you - some material found on wikis, irc logs and the like
...or even better send it to some of the CSSU developers/maintainers (me, Pali, merlin1991,...)

Thanks.


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