Desktop Lags under Heavy IO

pwaller · n00b Joined: 03 Sep 2007 Posts: 25

My Machine:

pwaller@jupiter ~ $ uname -a
Linux jupiter 2.6.22-suspend2 #2 SMP PREEMPT Mon Sep 3 00:55:46 UTC 2007 i686 Genuine Intel(R) CPU T2500 @ 2.00GHz GenuineIntel GNU/Linux

The lag I'm experiencing is most noticeable when I'm emerging or searching for files using find. Notably it affects the mouse and the keyboard. It makes typing almost impossible because it seems something is registering the key being pressed but not registering the key being released and so I get lots of a single keypress when trying to type.

I'm not really sure where to begin with trying to figure out what is causing this, can somebody recommend a starting point?

Cheers.

P.S. Can someone recommend a way of attaching my Kernel config to this post?

Ehnvis · Guru Joined: 13 Jun 2006 Posts: 305 Location: /dev/random

Do you have DMA running on your harddrives? Check with hdparm /dev/hdX or hdparm /dev/sdX, where X is the letter of the drive.

Easiest way to attach the kernel config is to open it up in an editor or view it in some way. Copy the text and paste it to here in code tags.
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HP NC 4010, Pentium-M 725 1.6GHz w/ 1Gb RAM, 60Gb Hitachi Travelstar.
Running Gentoo-2.6.21-r4 (again as 2.6.22 kernels hogs CPU), all but SD reader works fine.

tuam · l33t Joined: 04 May 2004 Posts: 755 Location: CGN, Germany

John R. Graham · Posted: Tue Sep 04, 2007 11:38 am Post subject: Re: Desktop Lags under Heavy IO

pwaller · n00b Joined: 03 Sep 2007 Posts: 25

http://rafb.net/p/3v2vGd88.html

energyman76b · Advocate Joined: 26 Mar 2003 Posts: 2009 Location: Germany

try cfq as default scheduler.

I had pretty good experiences with it. Better than with AS.

also, please post your dmesg - and maybe explain some of your config choices.
Memory hotplug yes? MSR only module? wtf?

and turn of the generic ide driver, if you are using a chipset driver. Or generic will 'steal' the device - and it is slower.

Also, turn off nmi-watchdog nmi_watchdog=0 as boot parameter. There are reports that it becomes less laggy that way.

do you really need all that scsi-crap? or the stuff in block? or all that fs? btw, if you are using reiserfs, turn of the 'Preempt big kernel log' - it is faster that way. 'Voluntary Preemption' might be better too and '300Hz' instead of 1000. if you are using a laptop, you really don't want 1000Hz, because it sucks down battery juice like a thristy camel water.

Maybe clean up your config. You can't have everything installed you turned on or turned on as module.. your kernel build-time will decrease a lot!
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Sadako · Posted: Tue Sep 04, 2007 5:34 pm Post subject:

energyman76b · Advocate Joined: 26 Mar 2003 Posts: 2009 Location: Germany

astor84 · Posted: Wed Sep 05, 2007 2:43 am Post subject:

You don't happen to have an SiS chipset do you? SiS chipsets are notorious for being unable to handle a lot of simultaneous IO.

pwaller · n00b Joined: 03 Sep 2007 Posts: 25

No SIS chipset. Sorry for the long delay.. thanks for the advice guys.

I tried some of it out (I haven't switched to the CFQ scheduler yet.)

Here is the latest kernel config, with unused stuff stripped out (but section comments remaining)
http://pastebin.ca/707923

Here is my dmesg output:
http://pastebin.ca/707925

Here is my lspci:
http://pastebin.ca/707928

I tried turning of my scsi stuff but managed to mess everything up. Is there an easy way to maintain multiple kernel configurations installed with the same version of the kernel? I had the problem where I changed stuff and couldn't boot at all because it didn't recognise my hard-disk. I'm using genkernel.. I figure there must be an easy way to do this.

So the options seem to have helped a little, but still when emerging I lose my system almost entirely, and watching a DVD is very jerky.

Thanks in advance guys.

- Peter

energyman76b · Advocate Joined: 26 Mar 2003 Posts: 2009 Location: Germany

pwaller · n00b Joined: 03 Sep 2007 Posts: 25

Cheers energyman. I will try this out over the next couple of hours and report back

- Pete

energyman76b · Advocate Joined: 26 Mar 2003 Posts: 2009 Location: Germany

and excuse me please, if I sound harsh

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Sadako · Posted: Sun Sep 23, 2007 2:48 pm Post subject:

pwaller · n00b Joined: 03 Sep 2007 Posts: 25

s'ok, your help outweighs your attitude.

I have to say though, I am worried about turning of the SCSI stuff. I think it caused me problems last time. And figuring out exactly what IDE driver to turn off is a pain, too.

Is there any way to keep my old, known-working kernel config around whilst trying out the new one?

energyman76b · Advocate Joined: 26 Mar 2003 Posts: 2009 Location: Germany

Sadako · Posted: Sun Sep 23, 2007 3:02 pm Post subject:

energyman76b · Advocate Joined: 26 Mar 2003 Posts: 2009 Location: Germany

Sadako · Posted: Sun Sep 23, 2007 3:05 pm Post subject:

Sadako · Posted: Sun Sep 23, 2007 3:08 pm Post subject:

energyman76b · Advocate Joined: 26 Mar 2003 Posts: 2009 Location: Germany

Sadako · Posted: Sun Sep 23, 2007 3:13 pm Post subject:

pwaller · n00b Joined: 03 Sep 2007 Posts: 25

Latest Kernel Config:
http://pastebin.ca/708088

Hey, I seem to have some improvement, but DMA is disabled.

I'm feeling really dumb, I can't figure out what I need to do to turn it on. I've grepped for DMA in the config, but to me it looks like all of the relevant options are on..?

I really appreciate the help guys.

Sadako · Posted: Sun Sep 23, 2007 3:55 pm Post subject:

What does `hdparm -d 1 /dev/hda` actually return, on both the command line and in dmesg?

Oh, energyman76b, I read up on the reiserfs and "Preempt the big kernel lock" thing, and apparently it's only the journalling code which makes use of it, however there isn't much else in the kernel which does use the kernel lock so I've disabled that preemption option.
Thanks for the tip off.
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energyman76b · Advocate Joined: 26 Mar 2003 Posts: 2009 Location: Germany

dmesg would be helpfull. And you should be able to turn on dma with hdparm (hdparm -d1 -u1 -c1 /dev/hda & the same for your cd drive like hdc..)
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