Subject: Re: SCSI performance degration figures
To: Toru Nishimura <nisimura@itc.aist-nara.ac.jp>
From: Chuck Silvers <chuq@chuq.com>
List: port-pmax
Date: 08/22/2001 23:20:36
hi,
were these iozone runs done with a filesystem or on a raw device?
if it was with a filesystem, you could also try a run with the performence
enhancements I've been working on:
ftp://ftp.netbsd.org/pub/NetBSD/misc/chs/ubc-perf/
grab the latest diff, put the new genfs_node.h file in sys/miscfs/genfs,
rebuild. this improves filesystem performance dramatically on old, slow
machines.
-Chuck
On Wed, Aug 22, 2001 at 04:43:04PM +0900, Toru Nishimura wrote:
> 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