Re: Slow Disk I/O with QPS M3 80GB HD

[Ben Collins]

On Mon, Dec 10, 2001 at 11:57:08PM -0800, H . J . Lu wrote:
> On Mon, Dec 10, 2001 at 08:34:52PM -0800, H . J . Lu wrote:
> > I have a very strange problem. The disk I/O of my QPS M3 80GB HD is
> > very slow under 2.4.10 and above. I got like 1.77 MB/s from hdparm.
> > But under 2.4.9, I got 14 MB/s on the same hardware. A 30GB HD has
> > consistent I/O performance under 2.4.9 and above on the same bus. Has
> > anyone else seen this? Does anyone have a large (>= 80GB) 1394 HD?
> > 
> 
> I did a binary search. 2.4.10-pre10 is the last good kernel. I got
> 
> # hdparm -t /dev/sda
> 
> /dev/sda:
>  Timing buffered disk reads:  64 MB in  4.40 seconds = 14.55 MB/sec

Have you checked the way that your ohci and sbp2 devices are detected
under each case? Most notably the max packet size.

Ben

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