From owner-freebsd-hackers Thu Nov 21 4:19:22 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 437B637B401 for ; Thu, 21 Nov 2002 04:19:21 -0800 (PST) Received: from chiark.greenend.org.uk (chiark.greenend.org.uk [193.201.200.170]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3A0CE43E42 for ; Thu, 21 Nov 2002 04:19:20 -0800 (PST) (envelope-from fanf@chiark.greenend.org.uk) Received: from fanf by chiark.greenend.org.uk with local (Exim 3.12 #1) id 18EqIh-000800-00 (Debian); Thu, 21 Nov 2002 12:19:19 +0000 Date: Thu, 21 Nov 2002 12:19:19 +0000 From: Tony Finch To: hackers@freebsd.org Subject: Re: cvs commit: src/bin/sleep sleep.c Message-ID: <20021121121919.D16558@chiark.greenend.org.uk> References: <200211170158.gAH1wJhc035731@apollo.backplane.com> <20021117034219.13731.qmail@web41201.mail.yahoo.com> <20021117034219.13731.qmail@web41201.mail.yahoo.com> <20021121020230.GA2107@HAL9000.homeunix.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20021121020230.GA2107@HAL9000.homeunix.com>; from dschultz@uclink.berkeley.edu on Wed, Nov 20, 2002 at 06:02:30PM -0800 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Wed, Nov 20, 2002 at 06:02:30PM -0800, David Schultz wrote: > Thus spake Tony Finch : > > > > Most of the BSS is mmapped zero pages that are copy-on-write, so in simple > > programs they should be mostly shared. See rtld-elf/map_object.c > > Once those pages are written to, the kernel must fault in a fresh > zero-filled page. Since the BSS typically holds uninitialized > data, we can probably assume that the program is going to > initialize most of it at some point, so there will be very few > shared BSS pages. I said "simple" to mean programs that don't use very much of libc and therefore shouldn't touch very much of libc's bss. Tony. -- f.a.n.finch http://dotat.at/ SELSEY BILL TO LYME REGIS:SOUTH TO SOUTHEAST 6 OR 7 EASING SOUTH TO SOUTHWEST 4 OR 5 FOR A TIME THEN INCREASING SOUTH TO SOUTHWEST 5 OR 6, PERHAPS OCCASIONALLY 7. RAIN OR SHOWERS, OCCASIONALLY HEAVY. GOOD TO MODERATE. ROUGH. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message