Date: Sun, 14 Mar 1999 13:35:28 +0100 From: Ollivier Robert <roberto@keltia.freenix.fr> To: Kenneth Merry <ken@FreeBSD.ORG> Cc: "FreeBSD SCSI Users' list" <freebsd-scsi@FreeBSD.ORG> Subject: Re: cvs commit: src/sys/cam cam_xpt.c Message-ID: <19990314133528.A4071@keltia.freenix.fr> In-Reply-To: <199903140515.VAA29957@freefall.freebsd.org>; from Kenneth Merry on Sat, Mar 13, 1999 at 09:15:39PM -0800 References: <199903140515.VAA29957@freefall.freebsd.org>
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According to Kenneth Merry:
> Log:
> Disable tagged queueing for the IBM DCAS drives. These drives have poor
> write performance when tagged queueing is enabled.
Do you call that poor performance ? I have two 4 gig drives and they don't
seem that slow for me...
Seeker 1...Seeker 3...Seeker 2...start 'em...done...done...done...
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
dcas4 256 2891 37.3 2534 9.8 1797 7.9 5913 48.2 5916 19.2 96.0 3.5
Writing the 256 Megabyte file, 'iozone.tmp'...95.656250 seconds
Reading the file...43.687500 seconds
IOZONE performance measurements:
2806251 bytes/second for writing the file
6144445 bytes/second for reading the file
ncr0: <ncr 53c875 fast20 wide scsi> rev 0x03 int a irq 9 on pci0.11.0
da1 at ncr0 bus 0 target 1 lun 0
da1: <IBM DCAS-34330W S65A> Fixed Direct Access SCSI-2 device
da1: 40.00MB/s transfers (20.00MHz, offset 15, 16bit), Tagged Queueing Enabled
da1: 4134MB (8467200 512 byte sectors: 255H 63S/T 527C)
da0 at ncr0 bus 0 target 0 lun 0
da0: <IBM DCAS-34330W S65A> Fixed Direct Access SCSI-2 device
da0: 40.00MB/s transfers (20.00MHz, offset 15, 16bit), Tagged Queueing Enabled
da0: 4134MB (8467200 512 byte sectors: 255H 63S/T 527C)
--
Ollivier ROBERT -=- FreeBSD: The Power to Serve! -=- roberto@keltia.freenix.fr
FreeBSD keltia.freenix.fr 4.0-CURRENT #70: Sat Feb 27 09:43:08 CET 1999
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