Arch Linux

ezacaria

Member

Registered: 2007-12-10

Posts: 113

sluggish X with high hard drive activity

Hello,

I'm running a box with a PATA drive and a SATA drive. When I launch a very HD-intensive process operating on the SATA drive, KDE is very unresponsive.

I tried the following:

- Lowered the priority of the process with nice -n 19. Helps but the mouse still stutters sometimes and there are some not-so-smooth moments
- Launched the same process in runlevel 3. Using emacs in the console and mc don't suffer so much as KDE, but it is still not totally smooth
- Changed the I/O scheduler for the drive: CFQ->anticipatory. Did not solve the problem.

I tested the drive with hdparm, the drive is in udma6 mode and reports some 60 Mb/s rates. I searched and found that for PATA drives the unmasq_irq setting could improve responsiveness under heavy load, but I don't know if this applies to the SATA drive, which is accessed as sdb*

Thanks!

Eduardo

cerbie

Member

Registered: 2008-03-16

Posts: 124

Re: sluggish X with high hard drive activity

Are you using any swap? The only 'normal' way you'd get this behavior, that I know of, is PIO mode (checked), and paging a lot. OTOH, does it happen only for KDE? Maybe KDE has some kind of service running that is monitoring activity and even doing writes...?

---

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

BeholdMyGlory

Member

Registered: 2008-08-30

Posts: 93

Re: sluggish X with high hard drive activity

As far as I know, a bug in the kernel is making the OS sluggish during large I/O operations, so there's not much to do about it for now. I think someone here at the forum made a small patch for the kernel, but I'm not sure how well it worked.

skottish

Forum Fellow

From: Here

Registered: 2006-06-16

Posts: 7,942

Re: sluggish X with high hard drive activity

There's a rather involved thread on the subject here:

http://bbs.archlinux.org/viewtopic.php?id=66131

ezacaria

Member

Registered: 2007-12-10

Posts: 113

Re: sluggish X with high hard drive activity

Hi,

I changed the swappiness, as described in one the above links. This improves the situation quite a lot, for example when copying files of size over 7 GB between drives.

Still, the data rates for copying are not satisfactory. In my old Gentoo installation (2.6.20), copying to a USB hard drive achieves 20-21 MB/s with good responsiveness. The SATA disk is accessed there as /dev/hde. But in the up-to-date Arch I only get around 12 MB/s (the drive is accesed as /dev/sdb).

Any views on this?

Thanks!

Eduardo