The following reply was made to PR kern/30531; it has been noted by GNATS.

From: Patrick Welche <prlw1@newn.cam.ac.uk>
To: gnats-bugs@netbsd.org, kern-bug-people@netbsd.org,
	netbsd-bugs@netbsd.org
Cc: bouyer@antioche.eu.org, thorpej@shagadelic.org
Subject: Re: kern/30531: lsilogic raid array crawls
Date: Wed, 13 Jul 2005 20:04:10 +0100

 The LSI21320-IS card has "IS" = "integrated striping", in other words
 mirroring. If I use its firmware utility to break the mirror back into
 two disks:
 
 sd0 at scsibus1 target 0 lun 0: <FUJITSU, MAS3735NP, 5B08> disk fixed
 sd0: 70007 MB, 27094 cyl, 8 head, 661 sec, 512 bytes/sect x 143374650 sectors
 sd0: sync (6.25ns offset 127), 16-bit (320.000MB/s) transfers, tagged queueing
 sd1 at scsibus1 target 1 lun 0: <FUJITSU, MAS3735NP, 5B08> disk fixed
 sd1: 70007 MB, 27094 cyl, 8 head, 661 sec, 512 bytes/sect x 143374650 sectors
 sd1: sync (6.25ns offset 127), 16-bit (320.000MB/s) transfers, tagged queueing
 
 then the simple test of
 
   dd if=/dev/rsd0d of=/dev/null bs=64k count=1000
 
 gives a rather more respectable speed of 78392344 bytes/sec (about 75MB/s)
 
 Any thoughts on how to spot what linux is doing that we aren't?
 (have kgdb set up + chip manual)
 
 Cheers,
 
 Patrick