From owner-freebsd-stable Fri Aug 9 14:13:23 2002 Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 7D95937B400 for ; Fri, 9 Aug 2002 14:13:19 -0700 (PDT) Received: from freeway.dcfinc.com (ip68-98-13-80.ph.ph.cox.net [68.98.13.80]) by mx1.FreeBSD.org (Postfix) with ESMTP id D131943E4A for ; Fri, 9 Aug 2002 14:13:18 -0700 (PDT) (envelope-from chad@freeway.dcfinc.com) Received: (from chad@localhost) by freeway.dcfinc.com (8.8.8/8.8.8) id OAA14669; Fri, 9 Aug 2002 14:12:48 -0700 (MST) (envelope-from chad) Date: Fri, 9 Aug 2002 14:12:48 -0700 From: "Chad R. Larson" To: kpieckiel@smartrafficenter.org Cc: Bosko Milekic , Mario Pranjic , freebsd-stable@FreeBSD.ORG Subject: Re: SMP kernel: FreeBSD vs. Linux 2.4.x Message-ID: <20020809141248.C14518@freeway.dcfinc.com> References: <20020809091008.A87124@unixdaemons.com> <20020809164411.GC78503@pacer.dmz.smartrafficenter.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-md5; protocol="application/pgp-signature"; boundary="vtzGhvizbBRQ85DL" Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20020809164411.GC78503@pacer.dmz.smartrafficenter.org>; from kpieckiel-freebsd-stable@smartrafficenter.org on Fri, Aug 09, 2002 at 12:44:11PM -0400 Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG --vtzGhvizbBRQ85DL Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Aug 09, 2002 at 12:44:11PM -0400, Kevin A. Pieckiel wrote: > But why was the kernel not threaded from the start? Threads aren't a > new concept, and when FreeBSD was born, it would make sense to > consider the advantages threads bring to userland code when > determining how the future of the kernel will unravel. Those > advantages would seem desirable for the kernel as well, would they > not? Again, I speak from ignorance of the internal workings/structure > of the kernel. I'm not trying to fault anyone for these early > decisions, just get a clearer picture of why it was developed this > way. Because FreeBSD wasn't developed from scratch in the current millennium. It is a direct, linear descendant from Bell Labs Unix that escaped and entered academia at Berkeley. Good news: About 13 years of continual development and bug fixes makes for one =very= stable system. Bad news: Not everything is state of the art. The Great Big Lock was implemented because it was the fastest way to get SMP running with the existing kernel code. Otherwise you have to worry about things like interrupts going off that were waited for by sleeping code, and what to do with the current context, etc. etc. -crl -- Chad R. Larson (CRL15) 602-953-1392 Brother, can you paradigm? chad@dcfinc.com chad@larsons.org larson1@home.com DCF, Inc. - 14623 North 49th Place, Scottsdale, Arizona 85254-2207 --vtzGhvizbBRQ85DL Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 5.0i for non-commercial use MessageID: lOIgvDd3JkMlf5zuwCBCY7xKxfKPQa9X iQA/AwUBPVQwTInljHhlkExeEQKwJQCgkGmDGvZ23QW6lnUP3jN4qdMgIPcAn0SP 1tgrUAh0qqQePuDJPvB/kEuA =gQ1I -----END PGP SIGNATURE----- --vtzGhvizbBRQ85DL-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message