slow harddrive access

Bung · n00b Joined: 30 Jul 2006 Posts: 8

Hi, thanks for looking,

I recently did a fresh install and am having some issues with my harddrive access. Whenever my computer is writing to the harddrive (like unpacking files in portage or downloading a large file) my computer will get slow/buggy . My music will skip, and windows and video will move slow. Someone in a chat said to make sure i had PREEMPT set in my kernel, so i have CONFIG_PREEMPT=y and CONFIG_PREEMPT_BKL=y, however im still getting the issue.

I have the basic partition scheme from the install docs, (boot) (swap) (root). Boot is ext2 and root is ReiserFS... here is some more info, hope it helps...

Thanks for any help!

emerge --info

Gentree · Posted: Wed Aug 16, 2006 9:08 am Post subject:

hdparm -tT /dev/hda will give you some info of drive speed . also check dmesg and /var/log files for any errors relating to drive errors

tail -f /var/log/messages

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Linux, because I'd rather own a free OS than steal one that's not worth paying for.
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Bung · n00b Joined: 30 Jul 2006 Posts: 8

Hi, thanks for the tips.

I dont see any error messages in dmesg (or when the comp is loading up) apart from fsck.ReiserFS not found.

This is a fresh install, however I had gentoo on here before, and it worked fine.

Ok with "hdparm -tT /dev/hda" I get the following;

/dev/hda:
Timing cached reads: 1808 MB in 2.00 seconds = 902.89 MB/sec
Timing buffered disk reads: 10 MB in 3.54 seconds = 2.83 MB/sec

However, when I have music playing, this command does NOT make it stutter or make my computer slow down at all. So I dont think this is a valid test.

I added a little CPU/Mem monitor just to see if maybe it was my ram or something, and tried downloading a file. While downloading the file, every 5 seconds my music will skip, and my cpu monitor (not to mention my little blue cpu light) flashes. While unpacking the file, my CPU monitor goes to full and my system becomes nearly inoperable. I really think I got something setup wrong. Please, any help would really be appreciated, I dont want to spend another 3 days doing the fresh install all over.

Here is a little info about the harddrive stuff in dmesg, however Im thinking this really must be some kernel option Ive missed, or some incompatibility between important system utilities ..

Bung · n00b Joined: 30 Jul 2006 Posts: 8

I was also suggested in #gentoo to set the following in my kernel:

go to processor type and features and set the timer frequency to 1000
preemption model is low latency desktop (this was already set)
in block layer that you choose deadline for your io scheduler

Unfortunately after booting to this kernel I tried installing acroread which downloads and unpacks a large file, and I still have the same problem. My system will laagggg.

razze · Posted: Thu Aug 17, 2006 7:00 am Post subject:

Hello!

Make sure you have DMA enabled for the drive. Can you please post the output of #hdparm -Ii /dev/hda as the buffered disk reads are waaaaay to low for a properly configured system (I believe it should be something around 20 MB/s for an ide HD)
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Gentree · Posted: Thu Aug 17, 2006 10:07 am Post subject:

Bung · n00b Joined: 30 Jul 2006 Posts: 8

Thanks for responding guys,

In the Device Drivers -> ATA/ATAPI/MFM/RLL section I already have, Is that ok:

[*] Generic PCI bus-master DMA support
[ ] Force enable legacy 2.0.X HOSTS to use DMA
[*] Use PCI DMA by default when available

# hdparm -Ii /dev/hda

Gentree · Posted: Thu Aug 17, 2006 2:44 pm Post subject:

that's fine.

just looking at your dmesg, try grep -i or grep for IDE.

I think you will find a msg about the slow down if it's cable related.

_________________
Linux, because I'd rather own a free OS than steal one that's not worth paying for.
Gentoo because I'm a masochist
AthlonXP-M on A7N8X. Portage ~x86

razze · Posted: Thu Aug 17, 2006 3:21 pm Post subject:

can you try

Gentree · Posted: Thu Aug 17, 2006 4:34 pm Post subject:

look all suboptions under PCI IDE chipset support in ATA/IDE section . make sure you have your mobo chipset support selected.

read the help on those items if you're not clear.

That should be a nice fast disk giving respectable timings simlar to mine.

_________________
Linux, because I'd rather own a free OS than steal one that's not worth paying for.
Gentoo because I'm a masochist
AthlonXP-M on A7N8X. Portage ~x86

Bung · n00b Joined: 30 Jul 2006 Posts: 8

thanks again for the help thus far fellas

Ok at first it looks like my dma was off:

.:chrome:. · Posted: Sun Aug 20, 2006 6:29 pm Post subject:

Gentree · Posted: Sun Aug 20, 2006 8:06 pm Post subject:

Glad we got you going, Bung.

Gentree · Posted: Sun Aug 20, 2006 8:29 pm Post subject:

just looked back over your posts.

if the message was fsck.reiserfs not found (pay attention to detail when posting) you need reiserfsprogs.

emerge -p world will probably show this as [N] , new.

personally I suggest you forget reiserfs, its rather slow for most things (see namesys' own data) and gets slower fairly quickly due to fragmentation.

Unless you feel ready for a non-std kernel and reiser4 (the above indicates you could hold off a bit on that one) I suggest you user ext3 for root partition.

out of interest how about posting you timings now.

_________________
Linux, because I'd rather own a free OS than steal one that's not worth paying for.
Gentoo because I'm a masochist
AthlonXP-M on A7N8X. Portage ~x86

Bung · n00b Joined: 30 Jul 2006 Posts: 8

hey man, thanks again

i am installing reiserfsprogs now, cheers...

here are my timings:

# hdparm -tT /dev/hda

/dev/hda:
Timing cached reads: 1552 MB in 2.00 seconds = 775.44 MB/sec
Timing buffered disk reads: 56 MB in 3.27 seconds = 17.12 MB/sec

thanks for the tip about ext3, if its possible to change my drive format without reinstalling (ill google that) then I will switch over.

Gentree · Posted: Mon Aug 21, 2006 6:39 pm Post subject:

read up on hdparm , that still seems a bit sluggish, you may be able to tweek it up.

Gentree · Posted: Mon Aug 21, 2006 8:24 pm Post subject:

PS if you have assigned all free space to root partition you may like to look at the gparted liveCD . It's a great tool for resizing and the liveCD will let you do the formatting and the above copying as well.

_________________
Linux, because I'd rather own a free OS than steal one that's not worth paying for.
Gentoo because I'm a masochist
AthlonXP-M on A7N8X. Portage ~x86

srwalter · n00b Joined: 10 Mar 2005 Posts: 11 Location: KY

Another thing that can cause this stuttering, particularly as regards music playback, is a poor choice for the block scheduler. I'm not sure if it is any longer the case, but it used to be that the default setting could cause some applications (i.e., music players) to be starved when a big read/write transaction was going on. I've found that the "cfq" scheduler works well.

"cat /sys/block/hda/queue/scheduler" will show you what choices you have and which one you're currently using (assuming you have plain IDE, sda if you're using SATA)

"echo cfg > /sys/block/hda/queue/scheduler" would set your scheduler to cfq. This would need to be done after every boot, so it could be put in /etc/conf.d/local.start

Gentree · Posted: Tue Aug 22, 2006 8:39 pm Post subject: