Multitasking Problem in Debian

[EndianX]

I have recently switched from Ubuntu to Debian. I am having some performance problems though, that I don't recall having in Ubuntu. If the disk is being used, I get horrible performance with Gnome or KDE.

For example, if I am copying a large file across my network, or if apt is running in a terminal window and is downloading/installing something, I can hardly get my mouse to move. I have to just wait for the process to be done.

Mouse movement, dragging windows, typing...are not all these things done in RAM? Should disk access cause such a huge problem? It isn't possible my swap is being used is it? My swap is 2 gigs and I have 1 gig of RAM.

Any help would be appreciated. Let me know if more information is needed.

Thanks,

[darthmandeep]

If the disk is being used, I get horrible performance with Gnome or KDE.

Have you used hdparm on your disk drive?

http://linuxdevcenter.com/pub/a/linu...29/hdparm.html

Enabling DMA on your hard drive is one of the most basic speed tweaks around. If your system swaps more to disk than you would like, set your /proc/sys/vm/swappiness to a value like 10.

BTW, I hate it when I have to register just to post one comment. Why can't more forums allow non-registered posters?

[EndianX]

I am afraid this did not help. Thank you though.

I suspect the main difference is in the kernel. In Ubuntu I was using 2.6 and in Debian I am using 2.4 (when I tried to do a debian install with the linux26 mode, it couldn't find my hard drive).

I just tried a sudo apt-get install kernal-image-2.6.8-2-386 but I got some "kernel panic" error when I tried to boot with it. Why would the 2.6 kernel work in Ubuntu and not Debian?

sudo hdparm -Tt /dev/hda

/dev/hda:
 Timing cached reads:   3096 MB in  2.00 seconds = 1548.00 MB/sec
 Timing buffered disk reads:    8 MB in  3.42 seconds =   2.34 MB/sec

sudo hdparm /dev/hda

/dev/hda:
 multcount    = 16 (on)
 IO_support   =  0 (default 16-bit)
 unmaskirq    =  0 (off)
 using_dma    =  0 (off)
 keepsettings =  0 (off)
 readonly     =  0 (off)
 readahead    =  8 (on)
 geometry     = 7752/240/63, sectors = 117210240, start = 0

Anybody have any ideas?

Thank you,

[burnit]

Take care about precompiled kernels: they can have trned on debug options that can slow down your computer... infact I always suggest to compile your own kernel for fitting only your needs.

[farslayer]

using_dma = 0 (off)

Right there is a huge performance hit to the Hard drive. you should WANT the drive to be using dma.

using_dma = 1 (on)

Consult the hdparm docs as previously recommended.

[antidrugue]

So...

sudo hdparm -d1 /dev/hda

And the kernel you are using right now?

uname -a

If you can't get "kernel-image-2.6.8-2-686 to work on your machine, and are using a 2.4 kernel,well...

If you are using the 2.4 kernel, then you should at least install those two patches (which are compatible with each other).

sudo apt-get install kernel-patch-2.4-preempt kernel-patch-2.4-lowlatency

But I really don't recommand sticking with the 2.4 kernel, with the machine you have it's a waste.

Compile your own kernel. It is very easy with Debian.

If you want to go there, I'll post the instructions.

I'm using a custom 2.6.14.4 vanilla kernel on Debian Sarge: performance has never been better.