From owner-freebsd-hackers@FreeBSD.ORG Wed Jan 26 17:37:49 2011 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 14D241065701 for ; Wed, 26 Jan 2011 17:37:49 +0000 (UTC) (envelope-from gljennjohn@googlemail.com) Received: from mail-ww0-f50.google.com (mail-ww0-f50.google.com [74.125.82.50]) by mx1.freebsd.org (Postfix) with ESMTP id 972B58FC16 for ; Wed, 26 Jan 2011 17:37:48 +0000 (UTC) Received: by wwf26 with SMTP id 26so1121554wwf.31 for ; Wed, 26 Jan 2011 09:37:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:date:from:to:cc:subject:message-id:in-reply-to :references:reply-to:x-mailer:mime-version:content-type :content-transfer-encoding; bh=eu8GNs63L0zk61aW6N6b7SLemyPhrOOd407SCahZwoQ=; b=MtWTvcLYtcz8HTFGLb9dkN2YfHUaYxd963peKuEtoLsmE/h1+p2PlYUFpm+gMJ+0DZ 5TQUBLXHDlmKm8t7JVpfSMO3t7+nEzGx9xlGgdqangGlMWhFt/Mdmxn4DFWaJs6DPK/h 11gFi4DLshVElWzqmFQY4rwdsWo/hJXr1hULI= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=date:from:to:cc:subject:message-id:in-reply-to:references:reply-to :x-mailer:mime-version:content-type:content-transfer-encoding; b=dV71A0ARuAcJ0MU/uSk8rj6iT26GC22JDNPArQSuJo0X7GKX4xWiu8NeRr0EvOoWu3 2YmnfSELxYtKro5fQc3Y8pBS8BEagv8xJ2U1VUy0xrhxrj2+XM1nli7uoO2jw5SsXatg fDTayosW5ZWiZvQEofSCoBg9GQa4G7T/9MLoI= Received: by 10.227.135.75 with SMTP id m11mr7824128wbt.122.1296063466396; Wed, 26 Jan 2011 09:37:46 -0800 (PST) Received: from ernst.jennejohn.org (p578E15B7.dip.t-dialin.net [87.142.21.183]) by mx.google.com with ESMTPS id y29sm5978679wbd.4.2011.01.26.09.37.44 (version=TLSv1/SSLv3 cipher=RC4-MD5); Wed, 26 Jan 2011 09:37:45 -0800 (PST) Date: Wed, 26 Jan 2011 18:37:43 +0100 From: Gary Jennejohn To: John Baldwin Message-ID: <20110126183743.56f6406c@ernst.jennejohn.org> In-Reply-To: <201101261140.14024.jhb@freebsd.org> References: <20110125234911.223d8f75@kan.dnsalias.net> <201101261140.14024.jhb@freebsd.org> X-Mailer: Claws Mail 3.7.8 (GTK+ 2.18.7; amd64-portbld-freebsd9.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: freebsd-hackers@freebsd.org, Mark Felder Subject: Re: rtld optimizations X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: gljennjohn@googlemail.com List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Jan 2011 17:37:49 -0000 On Wed, 26 Jan 2011 11:40:13 -0500 John Baldwin wrote: > On Wednesday, January 26, 2011 10:25:27 am Mark Felder wrote: > > On Tue, 25 Jan 2011 22:49:11 -0600, Alexander Kabaev > > wrote: > > > > > The only extra quirk that said commit > > > does is an optimization of a dlsym() call, which is hardly ever in > > > critical performance path. > > > > It's really not my place to say, but it seems strange that if an > > optimization is available people would ignore it because they don't think > > it's important enough. I don't understand this mentality; if it's not > > going to break anything and it obviously can improve performance in > > certain use cases, why not merge it and make FreeBSD even better? > > Many things that seem obvious aren't actually true, hence the need for > actual testing and benchmarks. > I can't claim to have rigorously benchmarked this, but I am running with a patched ld-elf.so.1 right now and can state that *subjectively* there is absolutely no difference in the perceived performance. firefox, opera and OpenOffice still seem to be dogs the first time they start up. Since this is all about perception I see no benefit in applying the patch, although it doesn't seem to have broken anything either. -- Gary Jennejohn (gj@)