From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1265 invoked by alias); 29 Nov 2012 16:00:08 -0000 Received: (qmail 1122 invoked by uid 22791); 29 Nov 2012 16:00:06 -0000 X-SWARE-Spam-Status: No, hits=-7.9 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,KHOP_THREADED,RCVD_IN_DNSWL_HI,RCVD_IN_HOSTKARMA_W,RP_MATCHES_RCVD,SPF_HELO_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; Thu, 29 Nov 2012 15:59:56 +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 qATFxp4A017049 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 29 Nov 2012 10:59:52 -0500 Received: from [127.0.0.1] (ovpn01.gateway.prod.ext.ams2.redhat.com [10.39.146.11]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id qATFxoEU022139; Thu, 29 Nov 2012 10:59:50 -0500 Message-ID: <50B78675.4010505@redhat.com> Date: Thu, 29 Nov 2012 16:00:00 -0000 From: Pedro Alves User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Yao Qi CC: Marc Khouzam , "'dje@google.com'" , "'gdb-patches@sourceware.org'" Subject: Re: [PATCH 2/2] new tracepoint downloaded MI notification. References: <1348793347-12556-1-git-send-email-yao@codesourcery.com> <1348793347-12556-3-git-send-email-yao@codesourcery.com> <20604.20455.105300.495734@ruffy2.mtv.corp.google.com> <509167D4.20007@redhat.com> <5091C0B0.5000508@codesourcery.com> <50AE6FCC.4020205@redhat.com> <50B7834B.3060508@codesourcery.com> In-Reply-To: <50B7834B.3060508@codesourcery.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit 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: 2012-11/txt/msg00871.txt.bz2 On 11/29/2012 03:46 PM, Yao Qi wrote: > On 11/23/2012 02:32 AM, Pedro Alves wrote: >> What about the case of connecting to a target that is tracing, after >> disconnected tracing? Do we already tell the frontend somehow which >> tracepoints are active on the target? Should tracepoints have an >> "installed on target" field? >> >> Yao Qi wrote: >>> >On 11/01/2012 03:09 AM, Marc Khouzam wrote: >>>> >>Now that GDB pushes new tracepoints to the target immediately, that >>>> >>use-case may not apply, but I wonder if there are other situations >>>> >>where some tracepoints will be on the target and other will not? >>> > >>> >Yes, the pending tracepoints won't be downloaded after tracing is started until they are resolved. The notification is required for this case. >> Ok. If the answer to my question above is yes, it might be this >> notification ends up unnecessary in favor of a generic >> =breakpoint-modified. > > Pedro, to make sure I don't misread your comments, I'd like to ask are you suggesting that we can add an 'installed on target' field for tracepoint in '=breakpoint-modified' notification? Well, sort of, but by side effect, since =breakpoint-modified includes all the fields of a breakpoint/tracepoint. Say you've set up a disconnected tracing session, and then disconnect. Later, you start a new clean gdb session, create a new tracepoint (never downloaded/installed on the target), and reconnect. At this point, GDB will fetch the target's tracepoint list, and sync it with GDB's. The frontend gets a =breakpoint-created for each of those uploaded tracepoints, but it has no clue why they were created / their installed status. You end up with some tracepoints that are installed, and some that aren't in GDB's list. Does the frontend know this today by some means I'm missing? If not, does fixing this mean adding an "installed" property to breakpoints/tracepoints? Say we added your new notification, and then fixed the above as I'm suggesting. At that point, this new tracepoint downloaded notification ends up being redundant. So I'm trying to get us to think with a broad perspective around the "installed on target" frontend needs. -- Pedro Alves