System is choppy, any ideas?

HeadHolio · Guru Joined: 10 Aug 2002 Posts: 445

Ok, I notice that when playing games, or when the system is under a little load (rsync, emerging...etc) my mouse is choppy. The choppyness seems to happen every 4 seconds or so. It also sometimes makes sound studder. I've tried three different kernels (a Gentoo-sources 2.4 kernel, a CK-Sources 2.4 kernel, and a CK-Sources 2.6 kernel) and I get the exact same result with each one. I've also checked to ensure that I have DMA enabled for my hard drive. I can't seem to figure this out. That last thing that I can think of is a rogue process running in the background or something, but I have no idea how to go about checking for that. Anyone care to lend a hand?

Riftwing · Apprentice Joined: 06 Oct 2002 Posts: 293

Erm if you're playing a game like ut2004 etc I doubt you'll get good performance if you're compiling something at the same time.
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HeadHolio · Guru Joined: 10 Aug 2002 Posts: 445

No no no..........I get choppy desktop performance while compiling, and I get choppy game performance with nothing else running. Glxgears gives me just over 5500 fps at 1024x768. But I can see the gears aren't running smooth, they studder.

electrofreak · l33t Joined: 30 Jun 2004 Posts: 713 Location: Ohio, USA

run 'top' to see if you have some process that is stealling the power. Also, definately use a 2.6 kernel, it has a lot less latency than the 2.4 kernels.

PsychoDad · Posted: Thu Aug 19, 2004 11:56 am Post subject:

enable DMA on your hardrive....
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HeadHolio · Guru Joined: 10 Aug 2002 Posts: 445

Ya thanks, but like I said in my original post....DMA is enabled. That was the first thing I checked. I've never heard of TOP before. I'll try running it and see what it shows.

HeadHolio · Guru Joined: 10 Aug 2002 Posts: 445

Ok, top shows me a lot, but I'm not sure what I'm looking for. Anyways, I see a bunch of processes, sometimes they change, and sometimes some are highlighted bold. But overall, I don't see any process taking up too much CPU load, except for things like Quake3 taking around 96-99%.

senectus · Guru Joined: 17 Jul 2003 Posts: 534

Uh.. not sure how its done but try to find out how to "nice" things with a high priority.. and "nice" quack3 at the top... ?
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HeadHolio · Guru Joined: 10 Aug 2002 Posts: 445

Ya I had already tried re-nicing X from 0 to -10, and then to -20. All of which did absolutely nothing for the studdering/choppy problem. Any other ideas?

aethyr · Veteran Joined: 06 Apr 2003 Posts: 1085 Location: NYC

Why not try a vanilla 2.6 kernel?

Are you running any services in the background (mysql, apache, sshd, ftp, etc...)?

[edit] As far as top:

HeadHolio · Guru Joined: 10 Aug 2002 Posts: 445

I could try a Vanilla 2.6 kernel but I thought that a CK kernel would give me the best desktop performance (mm-sources kernel wouldn't compile for me). I somehow doubt that it's a kernel related issue just because performance has been identicle on 3 different kernels so far. As for the memory, I think I'm getting something weird:

mattjgalloway · l33t Joined: 16 Mar 2004 Posts: 761 Location: Coventry, UK

I get studdery mouse and sound aswell.

You know the problem? I can only use vanilla sources. Any other sources and it goes studdery. I have tried gentoo-sources of the same version number as vanilla-sources. There's something wrong in the gentoo sources somewhere, but I just use vanilla - works fine then.

Try a vanilla 2.4.27 - I have that running sweet. I've tried 2.6.7 aswell which is also fine for me.
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HeadHolio · Guru Joined: 10 Aug 2002 Posts: 445

Ok, you guys talked me into it. When I get home I will start compiling a vanilla 2.6 kernel and a vanilla 2.4 kernel and give them both a try.

mattjgalloway · l33t Joined: 16 Mar 2004 Posts: 761 Location: Coventry, UK

Good stuff. You won't regret it

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jftuga · Posted: Fri Aug 20, 2004 3:57 pm Post subject:

Instead of running just 'top', try 'top -id1'. The -i toggles off idle processes and the -d sets the refresh time to 1 second. Once inside of top, you can press i to toggle the process list and press s to change the delay time, which can be fractions. You can even set the delay to .2 seconds, but then top becomes a cpu hog itself.

Press q quits out of top.

-John

mattjgalloway · l33t Joined: 16 Mar 2004 Posts: 761 Location: Coventry, UK

Alternatively press 'h' inside top for a run down on all the commands. You can even save your current setup which is useful. I find that I like a certain layout and like to come back to the same one. I have delay set to 2, it's nice and doesn't hog CPU!
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aethyr · Veteran Joined: 06 Apr 2003 Posts: 1085 Location: NYC

Actually, your memory usage is fine. Linux tends to put a lot of things in memory cache, thereby using up as much RAM as it can.

The important thing there is that your swap is hardly being touched (only 13 megs). If you had a memory problem, you'd also see a lot of swap space being used.

mattjgalloway · l33t Joined: 16 Mar 2004 Posts: 761 Location: Coventry, UK

Is lots of swap space being used a bad thing?

I get tonnes of swap usage with 1024mb RAM. The RAM is fine though, it's Crucial DDR3200 which runs through memtest as sweet as a chocolate gateaux on legs.

What's lots of swap space being used got to do with bad RAM?
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HeadHolio · Guru Joined: 10 Aug 2002 Posts: 445

Ya, the vanilla kernel was no help. If anything, it's a little worse.

mattjgalloway · l33t Joined: 16 Mar 2004 Posts: 761 Location: Coventry, UK

Doh!

It works for me :-(

What version did you try?

Also, what is your system setup? How much RAM, swap, CPU info, etc.
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tomchuk · Guru Joined: 23 Mar 2003 Posts: 317 Location: Brooklyn, NY

Sounds like the choppiness coincides with disc access, no? What kind of drives, partition layout, filesystem, ide controller, etc are you using?

HeadHolio · Guru Joined: 10 Aug 2002 Posts: 445

Ok, here are my specs:

Athlon 1600+ at 1400 MHz
768MB DDRAM at 266MHz
200MB Swap
Maxtor 40Gig Hard drive ATA133 8MB

Partion layout is:
10 gig mounted at "/" as a reiserfs
30 gig mounted at "/home" as a reiserfs
100 MB mounted at "/boot" as ext3

And here is some useful info from my dmesg:

mattjgalloway · l33t Joined: 16 Mar 2004 Posts: 761 Location: Coventry, UK

Well, for a start you only have 200MB swap space. Most people will say you need at *least* the amount og your RAM... I'm not sure how much of an affect that will have though.

Try a 2.4 kernel. I've had problems with 2.6 and I've also had problems with choppyness - maybe it's something similar with our hardware, who knows. I have no problems with choppyness together with 2.6-vanilla though. A 2.4-vanilla is worth a try though.
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tomchuk · Guru Joined: 23 Mar 2003 Posts: 317 Location: Brooklyn, NY

He started with a 2.4 kernel, if 2.6 is choppy, 2.4, in theory, should be much worse.

I'd agree that 200MB of swap isn't really enough and may cause some problems, but I can't see how it'd lead to choppiness.

Another thought: do you have kernel preemption turned on? Try turning it off.

Do you mind posting your config for your 2.6 kernel?

mattjgalloway · l33t Joined: 16 Mar 2004 Posts: 761 Location: Coventry, UK

I certainly agree that 2.4 *shouldn't* be any better than 2.6, but i'm just saying that I've had problems with 2.6 and I've also had problems with choppiness.

Do you have the correct drivers for your hard drive and other hardware in your kernel? Posting your config would be a good idea as tomchuk says.
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