From owner-freebsd-current Thu Mar 30 11:16:22 2000 Delivered-To: freebsd-current@freebsd.org Received: from mass.cdrom.com (mg137-078.ricochet.net [204.179.137.78]) by hub.freebsd.org (Postfix) with ESMTP id 5D1E937BF8D; Thu, 30 Mar 2000 11:15:58 -0800 (PST) (envelope-from msmith@mass.cdrom.com) Received: from mass.cdrom.com (localhost [127.0.0.1]) by mass.cdrom.com (8.9.3/8.9.3) with ESMTP id KAA00452; Thu, 30 Mar 2000 10:05:26 -0800 (PST) (envelope-from msmith@mass.cdrom.com) Message-Id: <200003301805.KAA00452@mass.cdrom.com> X-Mailer: exmh version 2.1.1 10/15/1999 To: Poul-Henning Kamp Cc: Bruce Evans , Mike Smith , Matthew Dillon , freebsd-current@freebsd.org Subject: Re: SMP buildworld times / performance tests In-reply-to: Your message of "Thu, 30 Mar 2000 13:37:32 +0200." <1274.954416252@critter.freebsd.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 30 Mar 2000 10:05:26 -0800 From: Mike Smith Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > >> Just following on from this, one thing that I can see immediately being > >> very important to me at least is a spinlock in the timecounter structure. > >> Calcru and various other things call microtime(), and we're going to want > >> to lock out updates and parallel accesses to the timecounter. What > >> should we be using for an interrupt-disabling spinlock? > > > >Nothing. Accesses to the timecounter struct are already MP safe and fast. > >Only the i8254 timecounter hardware currently needs interrupt-disabling, > >but it is hopefully never used on SMP machines. > > Worse. It is used by default on SMP machines which don't sport the > PIIX timecounter. ie. anything using the PIIX3 or older (think 440FX dual P6 systems, etc.) -- \\ Give a man a fish, and you feed him for a day. \\ Mike Smith \\ Tell him he should learn how to fish himself, \\ msmith@freebsd.org \\ and he'll hate you for a lifetime. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message