From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265794AbUBCEiM (ORCPT ); Mon, 2 Feb 2004 23:38:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265811AbUBCEiM (ORCPT ); Mon, 2 Feb 2004 23:38:12 -0500 Received: from cpe-24-221-190-179.ca.sprintbbd.net ([24.221.190.179]:54657 "EHLO myware.akkadia.org") by vger.kernel.org with ESMTP id S265794AbUBCEiJ (ORCPT ); Mon, 2 Feb 2004 23:38:09 -0500 Message-ID: <401F25A8.8030800@redhat.com> Date: Mon, 02 Feb 2004 20:38:00 -0800 From: Ulrich Drepper Organization: Red Hat, Inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7a) Gecko/20040118 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Ingo Molnar CC: john stultz , lkml Subject: Re: [RFC][PATCH] linux-2.6.2-rc2_vsyscall-gtod_B1.patch References: <1075344395.1592.87.camel@cog.beaverton.ibm.com> <401894DA.7000609@redhat.com> <20040129132623.GB13225@mail.shareable.org> <40194B6D.6060906@redhat.com> <20040129191500.GA1027@mail.shareable.org> <4019A5D2.7040307@redhat.com> <20040130041708.GA2816@mail.shareable.org> <4019E713.1010107@redhat.com> <20040130092939.GB3841@elte.hu> In-Reply-To: <20040130092939.GB3841@elte.hu> X-Enigmail-Version: 0.83.0.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > but i'm a bit worried about the apparent fact that adding 200 more > symbols (and making the vDSO a real DSO in essence) to abstract the > kernel syscalls is apparently unacceptable performance-wise. If this is > true then the whole dynamic linking architecture is much slower than it > should be, isnt it? If the syscall entry code in the vdso takes care of the multiplexing we do not have to add any symbols to the vdso's symbol table. There are no additional costs associated with adding more optimized syscalls other than the multiplexer and that cost would be constant if a jump table is used. For now, the simple single cmpl is sufficient. -- ➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖