From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Re: [parisc-linux] Remove __ldcw_align for PA-RISC 2.0 processors Date: Thu, 9 Jun 2005 15:46:15 +0100 Message-ID: <20050609144615.GA24611@parcelfarce.linux.theplanet.co.uk> References: <20050609054700.GA9450@colo.lackof.org> <200506091429.j59ETPwv008987@hiauly1.hia.nrc.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kyle@fattire.cabal.ca, parisc-linux@lists.parisc-linux.org To: John David Anglin Return-Path: In-Reply-To: <200506091429.j59ETPwv008987@hiauly1.hia.nrc.ca> List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: parisc-linux-bounces@lists.parisc-linux.org On Thu, Jun 09, 2005 at 10:29:24AM -0400, John David Anglin wrote: > Yes, you need ",co" to get rid of the 16-byte alignment requirement. > This causes the operation to be done in cache which is a performance > win. I think this is safe for SMP. While the ",co" completer was > added in PA 1.1, it wasn't required that it be supported. Thus, > I think we are stuck with 16-byte alignment on PA 1.1. Agreed. Fortunately, the only machines we care about that are both PA1.1 and SMP are the PA7200 based servers and workstations -- J200, J210, J210XC, D250, D260, D350, D360, K100, K200, K210, K400 and K410. Technically, the early T-class servers and some G, H, I class servers were also SMP PA1.1, but we don't really care about them. Anyway, it seems pointless to penalise the 64-bit machines for something that doesn't affect them. For userspace, it's obviously different. There, we have to cope with any PA processor, and thus have to use a "self aligning" lock, but the kernel can be fine tuned. -- "Next the statesmen will invent cheap lies, putting the blame upon the nation that is attacked, and every man will be glad of those conscience-soothing falsities, and will diligently study them, and refuse to examine any refutations of them; and thus he will by and by convince himself that the war is just, and will thank God for the better sleep he enjoys after this process of grotesque self-deception." -- Mark Twain _______________________________________________ parisc-linux mailing list parisc-linux@lists.parisc-linux.org http://lists.parisc-linux.org/mailman/listinfo/parisc-linux