Subject: SCSI performance degration figures
To: None <>
From: Toru Nishimura <>
List: port-pmax
Date: 08/22/2001 16:43:04
Ok, folks, here is the table of figures to show how badly DECstation
NCR MI SCSI performance was suffered.

K48     1.5K compiled at 2000-11-21
K67     1.5K                 -12-12  
S0      1.5S             2001-03-15
V2      1.5V                 -06-01
X1      1.5X                 -08-22

There were major technological reaps done between 1.5K and 1.5S.
I point here that NetBSD/pmax has not been useful until UBC buffer
throttling code was added by Jason T.  Figures were collected from the
three consecutive iterations of 40MB iozone with 25MHz MAXINE running
on an old slow Quntaum LPS 540.  The best values are choosen of each three. 

          K48           K67             S0              V2              X1
W sec.  36.38           35.79           72.13           55.60           72.98   
R sec.  29.79           29.83           34.96           28.61           38.27

W B/s   1,152,914       1,171,920         581,492         754,371      553,411
R B/s   1,407,957       1,406,069       1,199,743       1,426,027    1,083,799

With the introduction of UBC write/read performance is greatly
fluctuated by virtual memory activity.  Sometimes write performance
is worse than the best case figure with 5% or so.  Apparenly MIPS pmap
code must be examined and tuned for UBC to retrieve the lost performance.

Tohru Nishimura