From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 23190 invoked by alias); 7 Nov 2003 23:01:41 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 23182 invoked from network); 7 Nov 2003 23:01:40 -0000 Received: from unknown (HELO localhost.redhat.com) (207.219.125.105) by sources.redhat.com with SMTP; 7 Nov 2003 23:01:40 -0000 Received: from redhat.com (localhost [127.0.0.1]) by localhost.redhat.com (Postfix) with ESMTP id AA2372B8F; Fri, 7 Nov 2003 18:01:40 -0500 (EST) Message-ID: <3FAC2454.2030009@redhat.com> Date: Fri, 07 Nov 2003 23:01:00 -0000 From: Andrew Cagney User-Agent: Mozilla/5.0 (X11; U; NetBSD macppc; en-US; rv:1.0.2) Gecko/20030820 X-Accept-Language: en-us, en MIME-Version: 1.0 To: davidm@hpl.hp.com Cc: "J. Johnston" , gdb-patches@sources.redhat.com, Kevin Buettner Subject: Re: RFA: ia64 portion of libunwind patch References: <3FA2B71A.3080905@redhat.com> <3FA2CA1B.7000502@redhat.com> <16290.59502.799536.383397@napali.hpl.hp.com> <3FAC12D3.2070207@redhat.com> <16300.8192.489647.740612@napali.hpl.hp.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2003-11/txt/msg00141.txt.bz2 > On Fri, 07 Nov 2003 16:46:59 -0500, Andrew Cagney said: > > > Andrew> Would it be possible to define the interface so that, when > Andrew> dip-> u.ti.table_data is NULL, the code just fetches values > Andrew> from memory using the memory callbacks? i.e., don't require > Andrew> GDB to fetch the entire table but instead fetch the bits > Andrew> that are needed. > > Well, it's software, so anything is _possible_, but I'd rather not do > that, because it creates artificial differences between the > (speed-critical) local unwind case and the remote unwind case. > Furthermore, the unwind table is of a known size, relatively small, > and accessed fairly randomly (via binary search), so it is normally > preferable to read the table all at once and I'd rather design the API > for this common case. Your comparing the self unwind case (i.e., what happens when a program does a "throw") vs the external unwind case (i.e., like what GDB has to do)? Is fetching the table elements via a function, rather than a direct access, really that significant an overhead? Andrew