From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1724 invoked by alias); 24 Jan 2011 22:35:54 -0000 Received: (qmail 1639 invoked by uid 22791); 24 Jan 2011 22:35:53 -0000 X-SWARE-Spam-Status: No, hits=-1.8 required=5.0 tests=AWL,BAYES_00,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (38.113.113.100) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 24 Jan 2011 22:35:49 +0000 Received: (qmail 13416 invoked from network); 24 Jan 2011 22:35:46 -0000 Received: from unknown (HELO ?192.168.0.101?) (yao@127.0.0.2) by mail.codesourcery.com with ESMTPA; 24 Jan 2011 22:35:46 -0000 Message-ID: <4D3DFEBC.8030508@codesourcery.com> Date: Mon, 24 Jan 2011 22:35:00 -0000 From: Yao Qi User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.13) Gecko/20101208 Thunderbird/3.1.7 MIME-Version: 1.0 To: Jiri Olsa CC: gdb@sourceware.org Subject: Re: [RFC] gelf - user space probe debugger References: <20110124161020.GC3694@jolsa.brq.redhat.com> In-Reply-To: <20110124161020.GC3694@jolsa.brq.redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: 2011-01/txt/msg00107.txt.bz2 On 01/25/2011 12:10 AM, Jiri Olsa wrote: > hi, > > I started a debugger project. It's based on the user space backport > of optimized kprobes (djprobes) and RSP stub implementation. > First of all, it is a nice piece of work! > The debugger is implemented as a preloaded shared library, > which handles all the debugger work, hence no kernel ptrace > is needed. Here are some questions, and I am sorry if my questions go out of scope here. 1. Do you plan to handle signal without ptrace support? In ptrace-debugger, we can know every signal delivered to debuggee process. How can we do that in your probe-debugger? 2. Do you plan to support hardware single-step on x86? > > I'd like to ask for opinions if there'd be users for such thing, > and if it's worth to continue on this.. AFAIK, it is not easy to replace ptrace-based debugger by probe-based debugger completely. However, probe-based technology can be a complementary part to existing ptrace-based debugger, especially to efficient implementation of breakpoint/watchpoint/tracepoint in some cases. Shortly, it is good to put both ptrace-based and probe-based into single debugger, and maximize their advantages, and minimize their disadvantages. -- Yao (齐尧)