From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11372 invoked by alias); 20 Feb 2004 17:01:52 -0000 Mailing-List: contact gdb-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sources.redhat.com Received: (qmail 11356 invoked from network); 20 Feb 2004 17:01:51 -0000 Received: from unknown (HELO localhost.redhat.com) (216.129.200.20) by sources.redhat.com with SMTP; 20 Feb 2004 17:01:51 -0000 Received: from gnu.org (localhost [127.0.0.1]) by localhost.redhat.com (Postfix) with ESMTP id A73042B92; Fri, 20 Feb 2004 12:01:44 -0500 (EST) Message-ID: <40363D78.9080708@gnu.org> Date: Fri, 20 Feb 2004 17:01:00 -0000 From: Andrew Cagney User-Agent: Mozilla/5.0 (X11; U; NetBSD macppc; en-US; rv:1.4.1) Gecko/20040217 MIME-Version: 1.0 To: Elena Zannoni , Daniel Jacobowitz , David Carlton Cc: gdb@sources.redhat.com Subject: Re: Huge slowdown since 6.0 References: <20040218210927.GA16641@nevyn.them.org> <20040220050905.GA15209@nevyn.them.org> <16438.14300.323849.306261@localhost.redhat.com> In-Reply-To: <16438.14300.323849.306261@localhost.redhat.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2004-02/txt/msg00282.txt.bz2 > Daniel Jacobowitz writes: > > How can they possibly be to blame? Well, they are. And reverting the > > change for enumerators definitely won't do any harm. Take a look at > > this, read it two or three times if necessary - it took me about a > > dozen: > > > > > > - &objfile->static_psymbols, > > > > + cu_language == language_cplus > > > > + ? &objfile->static_psymbols > > > > + : &objfile->global_psymbols, > > > > If I swap "static" and "global", it reduces GDB startup time by roughly > > 40% for glibc with debug information, which contains a lot of C > > enumerators. I assume that is what you meant to do in the first place? > > If so I can recover the speed hit for C for GDB 6.1, and then address > > the larger issues with large numbers of global psymbols in HEAD after > > we branch. > > Another point in favor of the theory that conditional expressions are > bad. > > This should be fine, consider it preapproved. However, what you are > really saying is that qsort performance is really bad in case we have > lots of symbols to sort. But how many symbols? You didn't post the > numbers. Hmm, begs a few questions: - why do we load the symbols during startup? Load globals on demand? - why do we sort the symbols during startup? Use a hash (so that break main is fast) and sort when (break main is entered?) - why don't we do more while GDB is twiddling its thumbs in the event loop event loop? Andrew