Date: Tue, 15 Sep 1998 03:44:09 -0700 From: Mike Smith <mike@smith.net.au> To: Alfred Perlstein <bright@hotjobs.com> Cc: Mike Smith <mike@smith.net.au>, freebsd-current@FreeBSD.ORG Subject: Re: Download of FreeBSD 3.0-SNAP Message-ID: <199809151044.DAA00966@word.smith.net.au> In-Reply-To: Your message of "Tue, 15 Sep 1998 06:32:13 CDT." <Pine.BSF.3.96.980915062910.21829C-100000@bright.fx.genx.net>
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> > > > If you really wanted to play games with the queue sorter, you might > > want to go for a minimal distance insertion policy rather than a strict > > ladder sort. As Kirk pointed out, there's plenty of room for > > experimentation in this field. 8) > > you can easily starve processes far from the insertion point using an > algorithm like that, in fact you can almost DOS a machine unless some sort > of quantum is invlolved to compromise locallity over time elapsed since a > read/write has been queued. Natch; shortest seek in the last N slots in the queue is the trivial workaround. You can go totally nuts with disk scheduling, but it all basically boils down to not being able to tell what the disk has remembered (think segmented cache) and which transitions will really cost you. *shrug* TCQ to the rescue. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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