From owner-freebsd-chat Wed Oct 17 11:16:25 2001 Delivered-To: freebsd-chat@freebsd.org Received: from lariat.org (lariat.org [12.23.109.2]) by hub.freebsd.org (Postfix) with ESMTP id DE6B537B42B for ; Wed, 17 Oct 2001 11:16:15 -0700 (PDT) Received: from mustang.lariat.org (IDENT:ppp0.lariat.org@lariat.org [12.23.109.2]) by lariat.org (8.9.3/8.9.3) with ESMTP id MAA12684; Wed, 17 Oct 2001 12:15:56 -0600 (MDT) Message-Id: <4.3.2.7.2.20011017120858.046a58a0@localhost> X-Sender: brett@localhost X-Mailer: QUALCOMM Windows Eudora Version 4.3.2 Date: Wed, 17 Oct 2001 12:15:52 -0600 To: Dag-Erling Smorgrav , chat@FreeBSD.ORG From: Brett Glass Subject: Re: Breaking news: FreeBSD is "considering implementing a preemptible kernel" In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org At 09:40 AM 10/16/2001, Dag-Erling Smorgrav wrote: >Robert Love is writing a patch to make the Linux kernel preemptible, >and has some interesting ideas about FreeBSD: > >http://kerneltrap.com/article.php?sid=328&mode=thread&order=0 Kernel pre-emption is tough to retrofit into a kernel, but not hard to put in if you're writing one from scratch. SVS' "Integrity" (http://www.ghs.com/products/rtos/integrity.html) has had it for quite some time. The RTOS never turns off interrupts, though it does ignore those that come in while a previous interrupt from the same source is being handled. As for SMP: It's probably more efficient to have intelligent I/O and/or asymmetrical multiprocessing (i.e. one or more CPUs devoted exclusively to handling non-intelligent peripherals) than to have multiple general-purpose processors fielding I/O requests. --Brett To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message