Date: Sun, 06 Oct 2002 21:10:49 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: Nate Lawson <nate@root.org> Cc: freebsd-arch@FreeBSD.ORG, freebsd-smp@FreeBSD.ORG Subject: Re: Running independent kernel instances on dual-Xeon/E7500 system Message-ID: <3DA10949.218488B9@mindspring.com> References: <Pine.BSF.4.21.0210061941060.5534-100000@root.org>
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Nate Lawson wrote: > My dismissiveness was due to anticipating the direction this was going, > which is nicely shown by the response below. In short, dedicated > processors for IO were used in the minicomputer days but are wasteful > nowadays when you have lightweight interrupts and/or polling when > appropriate. Yet, I keep running into employers who want to pay people to do exactly that, particularly for offloading network processing to one processor, and running applications on the other. And then there's the Tigon II firmware rewrite for FreeBSD, to offload interrupt and copy processing. And CGD's work for Sibytes (NetBSD 64bit MIPS-based network coprocessor board) doing just that got the company sold to Broadcom for what, $700M? 8-). > If your scheduler sucks, fix it. If a device needs extra processing > equivalent to another N Ghz CPU, the vendor will add silicon. The "S" in > SMP is for symmetric, lest we forget. People keep saying that, and then keep not running interrupts in virtual wire mode, so that their delivery is "S" as in "symmetric"... ;^). Actually, NT proved that wiring particular interrupts to particular processors was the way to go -- that was one of the things they did to beat the Linux numbers in both the Netcraft and Ziff-Davis benchmarks... perfect symmetry isn't all that it's promised. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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