From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10894 invoked by alias); 2 Jan 2010 20:59:47 -0000 Received: (qmail 10883 invoked by uid 22791); 2 Jan 2010 20:59:47 -0000 X-SWARE-Spam-Status: No, hits=-2.4 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS 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; Sat, 02 Jan 2010 20:59:42 +0000 Received: from int-mx08.intmail.prod.int.phx2.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o02KxfCO019243 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Sat, 2 Jan 2010 15:59:41 -0500 Received: from host0.dyn.jankratochvil.net (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx08.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o02KxcKU020993 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sat, 2 Jan 2010 15:59:40 -0500 Received: from host0.dyn.jankratochvil.net (localhost [127.0.0.1]) by host0.dyn.jankratochvil.net (8.14.3/8.14.3) with ESMTP id o02KxcMe009484; Sat, 2 Jan 2010 21:59:38 +0100 Received: (from jkratoch@localhost) by host0.dyn.jankratochvil.net (8.14.3/8.14.3/Submit) id o02KxcRp009481; Sat, 2 Jan 2010 21:59:38 +0100 Date: Sat, 02 Jan 2010 20:59:00 -0000 From: Jan Kratochvil To: Guillaume Yziquel Cc: gdb@sourceware.org Subject: Re: watchpoint hangs. Message-ID: <20100102205938.GA9421@host0.dyn.jankratochvil.net> References: <4B3FB2BC.9040104@citycable.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4B3FB2BC.9040104@citycable.ch> User-Agent: Mutt/1.5.20 (2009-08-17) X-IsSubscribed: yes Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2010-01/txt/msg00023.txt.bz2 On Sat, 02 Jan 2010 21:55:24 +0100, Guillaume Yziquel wrote: > >(gdb) print box > >$1 = {0x0 } > >(gdb) watch box > >Watchpoint 2: box > >(gdb) continue > >Continuing. > > And it eats up 90% of one of my CPU from now on... As it printed "Watchpoint" and not "Hardware watchpoint" it means it had to use software watchpoint for some reason. Therefore it needs to singlestep the code which should work but it is very very slow. On amd64 (x86_64) there are only 4 hardware watch registers with 8 bytes range each, that is 32 bytes of maximum hardware-watchable bytes of memory. According to "{0x0 }" your requested memory range is probably larger. Try to reduce the watched memory range in your specific debugging case. Regards, Jan