Date: Tue, 17 Apr 2001 18:06:18 -0700 From: Alfred Perlstein <bright@wintelcom.net> To: Greg Lehey <grog@lemis.com> Cc: Matt Dillon <dillon@earth.backplane.com>, "Justin T. Gibbs" <gibbs@scsiguy.com>, Doug Barton <DougB@DougBarton.net>, "current @ freebsd . org" <current@FreeBSD.ORG> Subject: Re: Kernel preemption, yes or no? (was: Filesystem gets a huge performance boost) Message-ID: <20010417180618.Z976@fw.wintelcom.net> In-Reply-To: <20010418093212.A80877@wantadilla.lemis.com>; from grog@lemis.com on Wed, Apr 18, 2001 at 09:32:12AM %2B0930 References: <200104160259.f3G2xqs06321@aslan.scsiguy.com> <200104160616.f3G6GI973782@earth.backplane.com> <20010417011957.W976@fw.wintelcom.net> <20010418093212.A80877@wantadilla.lemis.com>
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* Greg Lehey <grog@lemis.com> [010417 17:02] wrote: > On Tuesday, 17 April 2001 at 1:19:57 -0700, Alfred Perlstein wrote: > > * Matt Dillon <dillon@earth.backplane.com> [010415 23:16] wrote: > >> > >> For example, all this work on a preemptive > >> kernel is just insane. Our entire kernel is built on the concept of > >> not being preemptable except by interrupts. We virtually guarentee > >> years of instability and bugs leaking out of the woodwork by trying to > >> make it preemptable, and the performance gain we get for that pain > >> is going to be zilch. Nada. Nothing. > > > > Pre-emption is mearly a side effect of a mutex'd kernel. > > > > The actual gains are in terms of parallel execution internally. > > Meaning if we happen to copyin() a 4 meg buffer we can allow more > > than one process to be completing some sort of work inside the > > kernel other than spinning on the giant lock. > > *sigh* Couldn't you have changed the subject line when discussing > something of this importance? I wasn't discussing, I was explaining. -- -Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org] Represent yourself, show up at BABUG http://www.babug.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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