From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 17 Oct 2002 15:11:55 +0200 (CEST) Received: from buserror-extern.convergence.de ([212.84.236.66]:10244 "EHLO hell") by linux-mips.org with ESMTP id ; Thu, 17 Oct 2002 15:11:54 +0200 Received: from js by hell with local (Exim 3.35 #1 (Debian)) id 182AQl-0000SZ-00; Thu, 17 Oct 2002 15:11:15 +0200 Date: Thu, 17 Oct 2002 15:11:15 +0200 From: Johannes Stezenbach To: "Maciej W. Rozycki" Cc: "Gleb O. Raiko" , "Kevin D. Kissell" , linux-mips@linux-mips.org Subject: Re: Once again: test_and_set for CPUs w/o LL/SC Message-ID: <20021017131115.GA1689@convergence.de> Mail-Followup-To: Johannes Stezenbach , "Maciej W. Rozycki" , "Gleb O. Raiko" , "Kevin D. Kissell" , linux-mips@linux-mips.org References: <3DAE872E.D5EF0E4D@niisi.msk.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4i 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: 471 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: js@convergence.de Precedence: bulk X-list: linux-mips On Thu, Oct 17, 2002 at 02:02:35PM +0200, Maciej W. Rozycki wrote: > On Thu, 17 Oct 2002, Gleb O. Raiko wrote: > > > Implement new sysmips then. > > I'm not sure if that's a good idea. Glibc alone uses test_and_set(), > exchange_and_add(), atomic_add() and compare_and_swap(). Do you want a > separate syscall for each of these functions? I think the ll/sc emulation > may be the best solution after all. At least it's most flexible and not > much slower if at all. Depends on your usage pattern. E.g. we don't run software that uses atomicity.h (i.e. no C++ code), but heavily use pthread_mutex_lock() etc. The few uses of atomicity.h internal to glibc don't warrant any optimizations. So, if the beql-Method would not exist, I would consider implementing a new sysmips for compare_and_swap(). Regards, Johannes