Copying file and CPU usage

vmelkon · 05-28-2008, 09:40 PM

Hello,

Is it normal that when I copy a file, the CPU usage goes to 100% while the copy is taking place?
I have Kubuntu 7.04 and also Suse 10.0 on different machines. Perhaps it is not making use of DMA transfer?
The only drivers I updated on both are the graphics drivers.
The Kubuntu machine stays up to date with online updates.

Anyone want to know system spec or it doesn't matter?

pinniped · 05-28-2008, 10:54 PM

For large files, copy will always be slow and take a lot of CPU time - even worse when copying over a slow or busy network, when swapping is happening, and when the source disk is being accessed by numerous other programs.

H_TeXMeX_H · 05-29-2008, 04:35 AM

What filesystem are you using ?

Also, what's the output of:

Code:

hdparm /dev/hda

where '/dev/hda' is the device node of your HDD.

Also I disagree with pinniped, on my computer copying even huge files does not use very much CPU time at all. However, I use JFS not ext3 like most people.

vmelkon · 05-29-2008, 08:38 AM

On Suse 10.0
#hdparm /dev/hda

/dev/hda:
multcount = 16 (on)
IO_support = 1 (32-bit)
unmaskirq = 1 (on)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 256 (on)
geometry = 38792/16/63, sectors = 39102336, start = 0
========================================
Yes, I have used ext3 on both machines. I don't remember is JFS was offered when I installed Suse 10.0

H_TeXMeX_H · 05-29-2008, 02:34 PM

Well, it's reporting that DMA is on

Code:

using_dma = 1 (on)

So, that's not the problem.

I know, most distros offer only ext3 as the filesystem. That's too bad, cuz it's performance is not as good as JFS or XFS. JFS is good for me because it is known for low CPU usage.

vmelkon · 05-30-2008, 06:34 AM

Quote:

Originally Posted by H_TeXMeX_H

Well, it's reporting that DMA is on

Code:

using_dma = 1 (on)

So, that's not the problem.

I know, most distros offer only ext3 as the filesystem. That's too bad, cuz it's performance is not as good as JFS or XFS. JFS is good for me because it is known for low CPU usage.

Perhaps I will chose JFS or XFS next time if I do a reinstall.
Thanks for the info.

H_TeXMeX_H · 05-30-2008, 03:52 PM

Sure, no problem. If anyone else knows more and has other explanations, feel free to add them. I'm not an expert you know.

grizly · 05-30-2008, 06:16 PM

run copy using nice, I love nice processes!

Quote:

$nice cp file1 file2 /destination

Will automatically renice the copy by 10 points! Works great in scripts as well!