Date: Fri, 14 Apr 1995 16:54:52 -0400 (EDT) From: Jeff Aitken <jaitken@cslab.cs.vt.edu> To: nate@trout.sri.MT.net (Nate Williams) Cc: rgrimes@gndrsh.aac.dev.com, freebsd-scsi@FreeBSD.org Subject: Re: SCSI target Message-ID: <199504142054.QAA31915@husky.cs.vt.edu> In-Reply-To: <199504141951.NAA29549@trout.sri.MT.net> from "Nate Williams" at Apr 14, 95 01:51:19 pm
next in thread | previous in thread | raw e-mail | index | archive | help
> > > Your not going to get much more out of *any* ISA controller. The 1542CF > > will do a little better, but basically your problem is the speed of > > the ISA bus bus mastering (typical max is 5MB/sec *burst*, sustainted > > goes down to about 3.7-4MB/sec). You should be getting about 3MB/sec > > out of your 1542B and I have not seen anthing better on ISA. > > I *should* be seeing 3MB/sec, but I've never got #'s even close. > > This is with 2.0R install created FS's. > > Writing the 32 Megabyte file, 'iozone.tmp'...31.257812 seconds > Reading the file...24.953125 seconds > > IOZONE performance measurements: > 1073473 bytes/second for writing the file > 1344698 bytes/second for reading the file Maybe I'm just not understanding something here, but shouldn't I be getting better than 3MB/s with both the NCR Fast-SCSI2 controller + a Micropolis Fast-SCSI2 drive? (486DX2/66, 16MB, PCI/ISA, 256K cache) % iozone 32 IOZONE: Performance Test of Sequential File I/O -- V1.16 (10/28/92) By Bill Norcott Operating System: POSIX 1003.1-1988 -- using fsync() Send comments to: norcott_bill@tandem.com IOZONE writes a 32 Megabyte sequential file consisting of 65536 records which are each 512 bytes in length. It then reads the file. It prints the bytes-per-second rate at which the computer can read and write files. Writing the 32 Megabyte file, 'iozone.tmp'...16.140625 seconds Reading the file...10.984375 seconds IOZONE performance measurements: 2078880 bytes/second for writing the file 3054742 bytes/second for reading the file % iozone 128 IOZONE: Performance Test of Sequential File I/O -- V1.16 (10/28/92) By Bill Norcott Operating System: POSIX 1003.1-1988 -- using fsync() Send comments to: norcott_bill@tandem.com IOZONE writes a 128 Megabyte sequential file consisting of 262144 records which are each 512 bytes in length. It then reads the file. It prints the bytes-per-second rate at which the computer can read and write files. Writing the 128 Megabyte file, 'iozone.tmp'...59.031250 seconds Reading the file...42.664062 seconds IOZONE performance measurements: 2273672 bytes/second for writing the file 3145920 bytes/second for reading the file -- Jeff Aitken jaitken@vt.edu
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199504142054.QAA31915>