From owner-freebsd-current Tue Apr 17 14: 7:48 2001 Delivered-To: freebsd-current@freebsd.org Received: from earth.backplane.com (earth-nat-cw.backplane.com [208.161.114.67]) by hub.freebsd.org (Postfix) with ESMTP id 64F6637B423 for ; Tue, 17 Apr 2001 14:07:46 -0700 (PDT) (envelope-from dillon@earth.backplane.com) Received: (from dillon@localhost) by earth.backplane.com (8.11.2/8.11.2) id f3HL7ei07632; Tue, 17 Apr 2001 14:07:40 -0700 (PDT) (envelope-from dillon) Date: Tue, 17 Apr 2001 14:07:40 -0700 (PDT) From: Matt Dillon Message-Id: <200104172107.f3HL7ei07632@earth.backplane.com> To: Alfred Perlstein Cc: "Justin T. Gibbs" , Doug Barton , "'current@freebsd.org'" Subject: Re: FW: Filesystem gets a huge performance boost References: <200104160259.f3G2xqs06321@aslan.scsiguy.com> <200104160616.f3G6GI973782@earth.backplane.com> <20010417011957.W976@fw.wintelcom.net> <200104171722.f3HHMpt94518@earth.backplane.com> <20010417130210.K976@fw.wintelcom.net> <200104172051.f3HKpAF06881@earth.backplane.com> <20010417135336.Q976@fw.wintelcom.net> Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG : :You need to settle dude, pre-emption isn't a goal, it's mearly a :_possible_ side effect. : :We're not aiming for pre-emption, we're aiming for more concurrancy. A goal of having more concurrency is laudable, but I think you are ignoring the costs of doing task switches verses the likely spin time for a mutex. The whole point of using fine-grained Mutexes is to not have significant performance-effecting collisions in the first place, so why bother to try to task switch if you wind up spining in one? The goal for Giant is to get rid of it, so why bother to implement preemption for Giant? The goal of taking an interrupt is to be able to take several interrupts in parallel on different cpu's, and they can't block anyway, so why try to turn interrupts into real threads? It just doesn't make sense, Alfred. You guys are trying to optimize things that don't need optimizing and my fear is that you will introduce so many bugs into the kernel that it will take us years to get it back to 4.x's level of reliability. The goals I see bandied about in the lists are at cross-purposes with each other. -Matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message