Subject: SCSI performance degration figures
To: None <email@example.com>
From: Toru Nishimura <firstname.lastname@example.org>
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.