From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 10 Nov 2006 18:40:22 +0000 (GMT) Received: from h155.mvista.com ([63.81.120.155]:34003 "EHLO imap.sh.mvista.com") by ftp.linux-mips.org with ESMTP id S20038621AbWKJSkS (ORCPT ); Fri, 10 Nov 2006 18:40:18 +0000 Received: from [192.168.1.248] (unknown [10.150.0.9]) by imap.sh.mvista.com (Postfix) with ESMTP id BF4B03EBE; Fri, 10 Nov 2006 10:39:53 -0800 (PST) Message-ID: <4554C770.10106@ru.mvista.com> Date: Fri, 10 Nov 2006 21:39:44 +0300 From: Sergei Shtylyov Organization: MontaVista Software Inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; rv:1.7.2) Gecko/20040803 X-Accept-Language: ru, en-us, en-gb MIME-Version: 1.0 To: Linux-MIPS Cc: compudj@krystal.dyndns.org, tt-dev@shafik.org Subject: [Fwd: [Ltt-dev] MIPS atomic operations, "sync"] Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 13174 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: sshtylyov@ru.mvista.com Precedence: bulk X-list: linux-mips Forwarding to the correct mail list... -------- Original Message -------- Subject: [Ltt-dev] MIPS atomic operations, "sync" Date: Fri, 10 Nov 2006 13:36:53 -0500 From: Mathieu Desnoyers To: lkml@vger.kernel.org, ltt-dev@shafik.org Hi, I am currently creating a "LOCK" prefix free and memory barrier free version of atomic.h to fulfill my tracer (LTTng) needs, which is to atomically update per-cpu data and have a minimal performance loss. I just came across the MIPS atomic.h and system.h implementations in 2.6.18 which brings a question : Why are the primitives in include/asm-mips/atomic.h using the "sync" instruction even in the UP case ? system.h cmpxchg only uses the sync in the SMP case. Mathieu OpenPGP public key: http://krystal.dyndns.org:8080/key/compudj.gpg Key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 _______________________________________________ Ltt-dev mailing list Ltt-dev@listserv.shafik.org http://listserv.shafik.org/mailman/listinfo/ltt-dev