From owner-freebsd-current Tue Nov 30 11:14:23 1999 Delivered-To: freebsd-current@freebsd.org Received: from mailman.zeta.org.au (mailman.zeta.org.au [203.26.10.16]) by hub.freebsd.org (Postfix) with ESMTP id 0E34814EA5 for ; Tue, 30 Nov 1999 11:14:16 -0800 (PST) (envelope-from bde@zeta.org.au) Received: from bde.zeta.org.au (beefcake.zeta.org.au [203.26.10.12]) by mailman.zeta.org.au (8.8.7/8.8.7) with ESMTP id GAA09624; Wed, 1 Dec 1999 06:21:24 +1100 Date: Wed, 1 Dec 1999 06:13:13 +1100 (EST) From: Bruce Evans X-Sender: bde@alphplex.bde.org To: Marcel Moolenaar Cc: Matthew Dillon , Ville-Pertti Keinonen , current@FreeBSD.ORG Subject: Re: kernel: -mpreferred-stack-boundary=2 ?? In-Reply-To: <38441BD2.5540BE94@scc.nl> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Tue, 30 Nov 1999, Marcel Moolenaar wrote: > Matthew Dillon wrote: > > > All I can say to that is "bleh". The real question is whether performance > > is actually improved significantly or not. If not, I'd sent a nasty email > > to the gcc folks :-) > > I guess only if you do have a PIII and are using the new instructions. > In most cases this has no effect whatsoever. Not counting the > significant code size increase. It's also useful for properly aligning doubles on the stack. I would have expected the most generally efficient way to align doubles and the new PIII obkects to be aligning the stack only in functions that have such objects on the stack. This requires at most one extra instruction: andl $~0xf,$esp 16-byte alignment Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message