From owner-freebsd-current Mon Jul 12 10: 8:30 1999 Delivered-To: freebsd-current@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [209.157.86.2]) by hub.freebsd.org (Postfix) with ESMTP id 741F71513B for ; Mon, 12 Jul 1999 10:08:22 -0700 (PDT) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.9.3/8.9.1) id KAA70338; Mon, 12 Jul 1999 10:06:14 -0700 (PDT) (envelope-from dillon) Date: Mon, 12 Jul 1999 10:06:14 -0700 (PDT) From: Matthew Dillon Message-Id: <199907121706.KAA70338@apollo.backplane.com> To: Poul-Henning Kamp Cc: Luoqi Chen , dfr@nlsystems.com, jeremyp@gsmx07.alcatel.com.au, freebsd-current@FreeBSD.ORG, mike@ducky.net Subject: Re: "objtrm" problem probably found (was Re: Stuck in "objtrm") References: <20136.931798322@critter.freebsd.dk> Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG :> p.s. I'm pretty sure that the lock prefix costs nothing on a UP system, :> and probably wouldn't be noticed on an SMP system either because the :> write-allocation overhead is already pretty bad. But I haven't tested :> it. : :it's actually quite expensive in terms of bus bandwidth because a lot of :things have to be synchronized and stalled... : :-- :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! It depends on which L1/L2 cache model Intel is using. I wouldn't expect it to be much more expensive then a standard read-modify-write, but I will run some tests on an SMP box between two user processes to get some hard numbers. -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message