From owner-freebsd-arch Sun Jan 20 16: 8:12 2002 Delivered-To: freebsd-arch@freebsd.org Received: from khavrinen.lcs.mit.edu (khavrinen.lcs.mit.edu [18.24.4.193]) by hub.freebsd.org (Postfix) with ESMTP id 0ABA737B402 for ; Sun, 20 Jan 2002 16:08:10 -0800 (PST) Received: (from wollman@localhost) by khavrinen.lcs.mit.edu (8.11.4/8.11.4) id g0L088333530; Sun, 20 Jan 2002 19:08:08 -0500 (EST) (envelope-from wollman) Date: Sun, 20 Jan 2002 19:08:08 -0500 (EST) From: Garrett Wollman Message-Id: <200201210008.g0L088333530@khavrinen.lcs.mit.edu> To: louie@TransSys.COM Subject: Re: 64 bit counters again X-Newsgroups: mit.lcs.mail.freebsd-arch In-Reply-To: References: Organization: MIT Laboratory for Computer Science Cc: arch@freebsd.org Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG In article you write: >On an SMP system, some sort of locking is required to reliably >update a 32 bit or 64 bit counter. [...] > - This can be a low-level architectural feature, such as the IA32 >LOCK prefix on an instruction to convert it into an atomic R-M-W >operation. Technically, atomic RMW is not considered locking. (Hence, the class of algorithms known as ``lock-free synchronization algorithms''.) -GAWollman -- Garrett A. Wollman | O Siem / We are all family / O Siem / We're all the same wollman@lcs.mit.edu | O Siem / The fires of freedom Opinions not those of| Dance in the burning flame MIT, LCS, CRS, or NSA| - Susan Aglukark and Chad Irschick To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message