From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 6 Mar 2003 00:36:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 6 Mar 2003 00:36:27 -0500 Received: from cpe-24-221-190-179.ca.sprintbbd.net ([24.221.190.179]:62686 "EHLO myware.akkadia.org") by vger.kernel.org with ESMTP id ; Thu, 6 Mar 2003 00:36:26 -0500 Message-ID: <3E66E101.8050009@redhat.com> Date: Wed, 05 Mar 2003 21:47:45 -0800 From: Ulrich Drepper Organization: Red Hat, Inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4a) Gecko/20030303 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Benjamin LaHaise CC: Andi Kleen , Linux Kernel Subject: Re: Better CLONE_SETTLS support for Hammer References: <3E664836.7040405@redhat.com> <20030305190622.GA5400@wotan.suse.de> <3E6650D4.8060809@redhat.com> <20030305212107.GB7961@wotan.suse.de> <3E668267.5040203@redhat.com> <20030305210856.B16093@redhat.com> <3E66C5F4.5000106@redhat.com> <20030306002945.A31972@redhat.com> In-Reply-To: <20030306002945.A31972@redhat.com> X-Enigmail-Version: 0.73.1.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Benjamin LaHaise wrote: > using the TLS segment everywhere slows everything down > a tiny bit. Don't do it for unthreaded programs. You completely (still!) fail to understand the issue. How can I take somebody who suggest using the stack as a pseudo thread register serious? You don't see the impact of this so you don't recognize who absolutely absurd this is. Wrt inthreaded apps: either TLS is used everywhere or not at all. Single threaded code uses library code which relies on TLS. And since TLS is part of the ABI there is not question about the "not at all". The remaining issue is how to do it with the least impact. For this I've proposed a method which does this (according to Andi's measurements) with the least impact. And nobody forces you to use the standard runtime environment. Go on, create your own. Then you won't have any penalties except one single 'if' in the context switching code which you hopefully can live with. Mark it with unlikely() for all I care. - -- - --------------. ,-. 444 Castro Street Ulrich Drepper \ ,-----------------' \ Mountain View, CA 94041 USA Red Hat `--' drepper at redhat.com `--------------------------- -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQE+ZuEB2ijCOnn/RHQRAnlwAJ4kcZ7FbESC+FIsOyn6Ia0wN8FskgCgvh/K SR1Ki1CnTe2QXq0Gn7TsvAY= =jJ0e -----END PGP SIGNATURE-----