Arch Linux

kraftman13

Member

Registered: 2009-02-12

Posts: 20

Re: Anyone else getting crappy performance lately?

Can someone still running 2.6.27 kernel post config please?

broch

Banned

From: L.A. California

Registered: 2006-11-13

Posts: 975

Re: Anyone else getting crappy performance lately?

Whatever's going on, Debian is much more responsive than Arch here...

I have to agree. I used Kubuntu and it was much more responsive. For example when I'm copying file from ntfs partition or when I'm splitting it Arch becames incredibly unresponsive and hangs for few seconds from time to time. I suppose those problems are related to not proper scheduler settings for desktop computers in Arch. We just get generic kernel and we need to fit it to our needs (different settings for desktops, different for servers etc.).

This is solution for some games under wine (from winehq forum):

Sounds like the same scheduler issue I was having introduced in 2.6.24. Try put this in /etc/sysctl.conf or /etc/sysctl.d/

Code:
kernel.sched_features=21
kernel.sched_batch_wakeup_granularity_ns=25000000
kernel.sched_min_granularity_ns=4000000

and then run sysctl -p

These options are not available unless "Kernel debugging"
(CONFIG_DEBUG_KERNEL) and "Collect sheduler debugging info"
(CONFIG_SCHED_DEBUG) in "Kernel hacking" are enabled so you most likely
need to recompile.

Maybe we need some tuning for desktops too?

so what you are suggesting is to fix problems with disk I/O scheduler (default CFQ) by adjusting CPU scheduler (default CFS)?

kraftman13

Member

Registered: 2009-02-12

Posts: 20

Re: Anyone else getting crappy performance lately?

so what you are suggesting is to fix problems with disk I/O scheduler (default CFQ) by adjusting CPU scheduler (default CFS)?

Not exactly. I thought problem can be in some kernel options enabled like (clearly theoretically) preemptible rcu etc. However it seems my problem gone when I deleted myself from disk group :>. Btw. just don't even think about changing CFQ to something else

fflarex

Member

Registered: 2007-09-15

Posts: 466

Re: Anyone else getting crappy performance lately?

Haven't noticed any performance issues with my desktop or apps, probably because my computer is ridiculously overpowered for my uses (but I'm curious now, I may need to pull up a system monitor and measure it). However, I have noticed that my boot time has increased significantly. It now takes a minute or more to unlock my LUKS encrypted volumes, and every so often udev will also take much longer than it should.

cerbie

Member

Registered: 2008-03-16

Posts: 124

Re: Anyone else getting crappy performance lately?

I wonder if it's some kind of priority inversion, scheduler, or maybe VFS-related changes? I don't do much w/ fancy DEs (back to Openbox, for the moment), but my PC certainly comes to a crawl when I run ls -R (it didn't use to, but I can't say exact config info for when the last time I needed to do it was), and most people seem to be complaining with some relation to disk activity. Just throwing it out there.

While IO schedulers can change things a bit, only anticipatory and no-op should make night and day differences (usually bad).

Edit, since I don't want to bring it to the top, really: I had real work that needed my desktop (as in making money), so I was not using Arch. By the time I got Arch back up and running, there was a newer kernel, and everything is fine with it (though KDEmod's networking is broken *sigh*).

Last edited by cerbie (2009-04-05 10:20:20)

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"If the data structure can't be explained on a beer coaster, it's too complex." - Felix von Leitner

kraftman13

Member

Registered: 2009-02-12

Posts: 20

Re: Anyone else getting crappy performance lately?

I wonder if it's some kind of priority inversion, scheduler, or maybe VFS-related changes? I don't do much w/ fancy DEs (back to Openbox, for the moment), but my PC certainly comes to a crawl when I run ls -R (it didn't use to, but I can't say exact config info for when the last time I needed to do it was), and most people seem to be complaining with some relation to disk activity. Just throwing it out there.

While IO schedulers can change things a bit, only anticipatory and no-op should make night and day differences (usually bad).

Do you use generic Arch Linux kernel and to what groups do you belong? I can run ls -R and it doesn't slow down my system in any way.

broch

Banned

From: L.A. California

Registered: 2006-11-13

Posts: 975

Re: Anyone else getting crappy performance lately?

so what you are suggesting is to fix problems with disk I/O scheduler (default CFQ) by adjusting CPU scheduler (default CFS)?

Not exactly. I thought problem can be in some kernel options enabled like (clearly theoretically) preemptible rcu etc. However it seems my problem gone when I deleted myself from disk group :>. Btw. just don't even think about changing CFQ to something else

so?
what have problems with disk I/O to do with CPU scheduler settings and RCU?

kraftman13

Member

Registered: 2009-02-12

Posts: 20

Re: Anyone else getting crappy performance lately?

so what you are suggesting is to fix problems with disk I/O scheduler (default CFQ) by adjusting CPU scheduler (default CFS)?

Not exactly. I thought problem can be in some kernel options enabled like (clearly theoretically) preemptible rcu etc. However it seems my problem gone when I deleted myself from disk group :>. Btw. just don't even think about changing CFQ to something else

so?
what have problems with disk I/O to do with CPU scheduler settings and RCU?

Who said those are I/O problems? I have already posted what solved my problem. I didn't look at kernel config and RCU was just example (clearly theoretically). So?

Last edited by kraftman13 (2009-02-28 14:55:02)