Re: 2.4.20-pre2-ac4 IDE is slow

From: Athanasius (
Date: Fri Aug 23 2002 - 06:01:52 EST

On Thu, Aug 22, 2002 at 01:59:45PM -0400, Rob Speer wrote:
> I'm going from 2.4.19 to 2.4.20-pre2-ac4 and the hard drive is noticably
> slower in the new version. (It doesn't use DMA in either version - I
> wish it did in ac4, but that's a separate problem.)
> What I seem to remember from the other message is that there's some
> parameter that can be changed to bring the speed back up. Could someone
> tell me what it is?
> If it helps: output of hdparm /dev/hda
> /dev/hda:
> multcount = 0 (off)
> IO_support = 0 (default 16-bit)

  This could be part of the problem too? I don't think I set anything
specific to get to 32bit on my system. Hmmm, the multcount too?
I'm starting to think, if this is your output from 2.4.20-pre2-ac4 that
you're hitting a bug in the current code which is REALLY not doing the
right thing for your controller.

> unmaskirq = 0 (off)

  Try hdparm -u1 /dev/hda

> using_dma = 0 (off)

  And may as well use -d1 too if it works on the device (yes, I know you
said neither kernel enabled it per default). Then you're after finding
which DMA mode the IDE bus and drive can do, 'man hdparm' for the
possible values (like -X69 if it's all ATA100 capable for UDMA5).
  With a 60GB Maxtor and an 80pin cable I use:

        /sbin/hdparm -u1 -d1 -X69 /dev/hda

root@emelia:~# hdparm -t -T /dev/hda

 Timing buffer-cache reads: 128 MB in 0.52 seconds =246.15 MB/sec
 Timing buffered disk reads: 64 MB in 2.03 seconds = 31.53 MB/sec

Although I'm wondering if with ATA100 and UDMA5 I should be seeing even
better than that.



- Athanasius = Athanasius(at) /
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	   "And it's me who is my enemy. Me who beats me up.
Me who makes the monsters. Me who strips my confidence." Paula Cole - ME

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