From owner-freebsd-smp Tue Sep 21 17:25:14 1999 Delivered-To: freebsd-smp@freebsd.org Received: from lor.watermarkgroup.com (lor.watermarkgroup.com [207.202.73.33]) by hub.freebsd.org (Postfix) with ESMTP id DD8A914BD8; Tue, 21 Sep 1999 17:25:09 -0700 (PDT) (envelope-from luoqi@watermarkgroup.com) Received: (from luoqi@localhost) by lor.watermarkgroup.com (8.8.8/8.8.8) id UAA25595; Tue, 21 Sep 1999 20:25:08 -0400 (EDT) (envelope-from luoqi) Date: Tue, 21 Sep 1999 20:25:08 -0400 (EDT) From: Luoqi Chen Message-Id: <199909220025.UAA25595@lor.watermarkgroup.com> To: current@FreeBSD.ORG, phk@FreeBSD.ORG, smp@FreeBSD.ORG Subject: Re: Testers please! Sender: owner-freebsd-smp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > If you have a PIIX4 based SMP system and run current, could you > please try out this patch: > > http://phk.freebsd.dk/piix/ > > I'm very interested in hearing if there are any measurable difference > apart from clock granularity being 3 times better. > > -- > Poul-Henning Kamp FreeBSD coreteam member > phk@FreeBSD.ORG "Real hackers run -current on their laptop." > FreeBSD -- It will take a long time before progress goes too far! > This reminds me about the usage of TSC counter on SMP. First even though we don't use TSC for time keeping on SMP, the TSC frequency from calibration is still valid (at least for BSP), and we can show it in the cpu identification message. Second, the listed reason for not using TSC on SMP is the inability to synchronize TSCs on all cpus. My question is, is it really necessary? TSC is initialized to 0 at hardware reset, which should happen to all CPUs at the same time (invalid assumption?), in another words, all TSCs should be automatically synchronized. -lq To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message