A wee bit slow

TippExed · 08-28-2003, 11:23 AM

Hi,

Has anyone else experienced slow access to disks in debian? I installed a second knoppix 3.2 installation and updated it to sid, but ever since disk access has been a tad slower and it causes the KDE gui to slow down and become jittery. This only happens with data above 20meg, but that never really hurt before... the console might become unresponsive for the duration of the copy, etc, but the gui wasn't that affected. Even at 20 it's only for a sec or two, but it gets worse with size. Maybe I just never noticed it before?

I haven't used the experimental branch of debian before, and just want to know if it's normal or there's something to speed it up a wee bitty.

Also after the upgrade the root partition doesn't mount as read only for an fsck at the start of boot. This is no bother, I only mention it in case it's related...

Chris

fancypiper · 08-28-2003, 11:40 AM

What are your hdparm settings/timings?

Code:

Thu Aug 28 12:39pm root@uilleann ~ # hdparm /dev/hda

/dev/hda:
 multcount    = 16 (on)
 I/O support  =  0 (default 16-bit)
 unmaskirq    =  0 (off)
 using_dma    =  1 (on)
 keepsettings =  0 (off)
 nowerr       =  0 (off)
 readonly     =  0 (off)
 readahead    =  8 (on)
 geometry     = 4865/255/63, sectors = 78165360, start = 0
 busstate     =  1 (on)
Thu Aug 28 12:39pm root@uilleann ~ # hdparm -Tt /dev/hd{a,a,a}

/dev/hda:
 Timing buffer-cache reads:   128 MB in  1.08 seconds =118.52 MB/sec
 Timing buffered disk reads:  64 MB in  1.45 seconds = 44.14 MB/sec

/dev/hda:
 Timing buffer-cache reads:   128 MB in  1.08 seconds =118.52 MB/sec
 Timing buffered disk reads:  64 MB in  1.46 seconds = 43.84 MB/sec

/dev/hda:
 Timing buffer-cache reads:   128 MB in  1.07 seconds =119.63 MB/sec
 Timing buffered disk reads:  64 MB in  1.46 seconds = 43.84 MB/sec
Thu Aug 28 12:40pm root@uilleann ~ #

TippExed · 08-30-2003, 12:44 PM

Hi,

They are

root@arwen:/home/faramir# hdparm /dev/hdd

/dev/hdd:
multcount = 16 (on)
IO_support = 1 (32-bit)
unmaskirq = 1 (on)
using_dma = 0 (off)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 8 (on)
geometry = 155061/16/63, sectors = 156301488, start = 0
root@arwen:/home/faramir# hdparm -Tt /dev/hd{d,d,d}

/dev/hdd:
Timing buffer-cache reads: 1056 MB in 2.00 seconds = 528.00 MB/sec
Timing buffered disk reads: 22 MB in 3.10 seconds = 7.10 MB/sec

/dev/hdd:
Timing buffer-cache reads: 1044 MB in 2.00 seconds = 522.00 MB/sec
Timing buffered disk reads: 22 MB in 3.01 seconds = 7.31 MB/sec

/dev/hdd:
Timing buffer-cache reads: 1044 MB in 2.00 seconds = 522.00 MB/sec
Timing buffered disk reads: 22 MB in 3.03 seconds = 7.26 MB/sec
root@arwen:/home/faramir#

Is it the DMA then? How can you turn DMA on?

Cheers,
Chris

TippExed · 08-30-2003, 01:01 PM

Yeah it's the DMA. The other hd install has timings and results similar to the ones fancypiper gave.

root@willow:/home/danx# hdparm /dev/hdd

/dev/hdd:
multcount = 16 (on)
IO_support = 1 (32-bit)
unmaskirq = 1 (on)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 8 (on)
geometry = 155061/16/63, sectors = 156301488, start = 0
root@willow:/home/danx# hdparm -Tt /dev/hd{d,d,d}

/dev/hdd:
Timing buffer-cache reads: 128 MB in 0.51 seconds =250.98 MB/sec
Timing buffered disk reads: 64 MB in 1.39 seconds = 46.04 MB/sec

/dev/hdd:
Timing buffer-cache reads: 128 MB in 0.51 seconds =250.98 MB/sec
Timing buffered disk reads: 64 MB in 1.38 seconds = 46.38 MB/sec

/dev/hdd:
Timing buffer-cache reads: 128 MB in 0.51 seconds =250.98 MB/sec
Timing buffered disk reads: 64 MB in 1.39 seconds = 46.04 MB/sec
root@willow:/home/danx#

fancypiper · 08-30-2003, 01:03 PM

Is the file /etc/rc.d/rc.local on your system? If so, try these settings out and check the timings after changing each one.

hdparm -d1 -u1 -m16 -c3 /dev/hdd

If that drive is a slave to a CDROM, it will be slower than if on an IDE cable with only hard drives attached.

See this article:

# Hard drive tweak
Speeding up Linux Using hdparm
Not mentioned in the article but could possibly freeze the box:
UDMA 33/66/100. Add the -X option, and then this number i.e. (-X 69)
-X 33 ====> Multiword DMA
-X 66 ====> ATA-33 (UDMA2)
-X 68 ====> ATA-66 (UDMA4)
-X 69 ====> ATA-100 (UDMA 5)

I can't tell any difference with the X settings, myself.

HappyTux · 08-30-2003, 04:05 PM

On your Knoppix install edit the file /etc/init.d/bootmisc.sh and uncomment the hdparm line that should already be at the bottom of the file. BTW if you had booted Knoppix with the dma cheat code before you installed it would have been turned on by default you may also want to use the line suggested above instead of just the hdparm -qd1 /dev/hdd that will be there.

TippExed · 08-31-2003, 04:45 PM

Hi,

Cheers guys. I reinstalled debian sid and watched what it did. It replaces /etc/init.d/bootmisc.sh which is where Knoppix calls hdparm to set dma. Copying the two lines from a backup to the end of the file fixed it.

Cheers,
Chris