From: jhenders@jonh.wimsey.bc.ca (John Henders) Subject: Re: SCSI Performance (Yet Again) Date: Tue, 24 Aug 1993 00:59:14 GMT
ws@xivic.bo.open.de (Wolfgang Schelongowski) writes:
>How about
> date;dd if=/dev/sda of=/dev/null bs=131072 count=512;date
A more accurate measure of the scsi code, IMHO, would be to use code
which would use scsi read and write instructions to do real low level
i/o, removing all other variables.
>That took 69 seconds => 950 KByte/sec for raw I/O. Under BSDI,
>the numbers are 36 seconds on /dev/rsd0a => 1820 KByte/sec.
>As I'm still running 0.99 pl6 the numbers for Linux may have
>changed (hopefully to the better). Can somebody test it and
>post the results so we have _numbers_ to compare and not
>assumptions ?
>My System: noname 486/33, AHA1542B, Fuji M2624FA. It makes no
>difference for Linux whether I use async or sync SCSI.
I ran the above test and got 103 seconds, with a 386/40 and a Maxtor
120 HD. A test for scsi i/o should not be affaected by processor speed,
should it?
-- John Henders GO/MU/E d* -p+ c+++ l++ t- m--- s/++ g+ w+++ -x+