Date: Mon, 25 Oct 1999 08:40:43 -0400 From: "Michael Sinz" <Michael.Sinz@sinz.org> To: "Geoff Buckingham" <geoffb@chuggalug.clues.com> Cc: "Gerard Roudier" <groudier@club-internet.fr>, "Mike Sinz" <Michael@sinz.org>, "Randell Jesup" <rjesup@wgate.com>, "scsi@FreeBSD.ORG" <scsi@FreeBSD.ORG> Subject: Re: FreeBSD 3.2 / Slow SCSI Dell PowerEdge 4300 Message-ID: <199910251239.IAA28752@vixen.sinz.org>
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On Mon, 25 Oct 1999 10:58:47 +0100, Geoff Buckingham wrote: >On Wed, Oct 20, 1999 at 10:01:46AM -0400, Michael Sinz wrote: >> >> IMHO: >> For a general purpose server, one must assume that the special case of >> the I/O working out to be single threaded will not happen. Multiple things >> will be going on and the working set will be larger than the cache size. >> A bit of overhead added to the "simple" cases will make the general >> operation better. Benchmarks, however, may well show this as slower >> since some extra overhead had to be added. Benchmarks would need to >> become much more complex in order to show the real benefit or lack of >> benefit for any one technique. >> >Which brings us back to the question as to wether or not disabling TAGs for >WDE * is the correct thing to do? IMHO it is not. For the general case I would say that disabling TAGS is not worth the few specific case performance improvements (most of which are benchmark-only) -- Michael Sinz -- Director of Research & Development, NextBus Inc. mailto:michael.sinz@nextbus.com --------- http://www.nextbus.com My place on the web ---> http://www.users.fast.net/~michael_sinz To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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