Subject: slowdown with MI scsi on pmax (ds5000/200)
To: None <,>
From: Chuck Silvers <>
List: tech-kern
Date: 05/21/2001 00:35:47

I went back to run some benchmarks on my decstation 5000/200 again
first the first time in about a month, and I find that scsi performance
has dropped considerably.

in the 1.5.1_ALPHA kernel that I've been using as my control case,
8000 64k writes to a raw device took 173 seconds, and as of about
a month ago it took a comparable amount of time in -current.
today's -current takes 258 seconds to do the same writes.

could someone who knows the scsi code take a look at this?
a similar test on a pc doesn't show any slowdown, so I'm not sure whether
the problem is in the scsipi code that only shows up on slow machines
or the ncr53c9x code.  or something else entirely.