From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20606 invoked by alias); 21 Jul 2011 18:43:46 -0000 Received: (qmail 20598 invoked by uid 22791); 21 Jul 2011 18:43:46 -0000 X-SWARE-Spam-Status: No, hits=-7.0 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,SPF_HELO_PASS,TW_FD X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 21 Jul 2011 18:43:24 +0000 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p6LIhG7V023665 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 21 Jul 2011 14:43:16 -0400 Received: from host1.jankratochvil.net (ovpn-116-20.ams2.redhat.com [10.36.116.20]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id p6LIhDkL021764 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 21 Jul 2011 14:43:15 -0400 Received: from host1.jankratochvil.net (localhost [127.0.0.1]) by host1.jankratochvil.net (8.14.4/8.14.4) with ESMTP id p6LIhD6h010816; Thu, 21 Jul 2011 20:43:13 +0200 Received: (from jkratoch@localhost) by host1.jankratochvil.net (8.14.4/8.14.4/Submit) id p6LIhCf0010811; Thu, 21 Jul 2011 20:43:12 +0200 Date: Thu, 21 Jul 2011 20:10:00 -0000 From: Jan Kratochvil To: Pedro Alves Cc: Sergio Durigan Junior , gdb-patches@sourceware.org Subject: Re: [PATCH] On-demand loading of shlib's debuginfo Message-ID: <20110721184311.GA10555@host1.jankratochvil.net> References: <201107211158.45196.pedro@codesourcery.com> <201107211936.04731.pedro@codesourcery.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201107211936.04731.pedro@codesourcery.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2011-07/txt/msg00594.txt.bz2 On Thu, 21 Jul 2011 20:36:04 +0200, Pedro Alves wrote: > Oh, well:-) I thought the separation was good, as: > > - target sections are used for "set trust-readonly-sections on" > and similar fallbacks to reading memory from the exec, which > requires separate dso lazy load points (disassembly? printing > some address?). > > - its not clear to me the pc -> dso mapping from the link map is > faster than from the bfd in all scenarios. E.g., on remote > targets, it may be faster to get at the bfd info on the host, than > to remote read memory from the target. I agree the remote targets may give opposite performance benefits. I think it would be good to have both parts at hand to play with pros and cons. So far this patch needs explicit enable anyway as it breaks most of the non-backtrace commands. > - I was curious on how much lazing debug info alone was helping, > vs lazing the bfd reads. I had some very brief benchmark: 0m24.824s -> 0m12.885s (cold disk cache with warm cache for gdb) F15.x86_64, therefore with .gdb_index. This is by a variant of this patch - that is still with mapping bfds for target sections, on HDD (not SSD). And sure everything with linux-nat. Thanks, Jan