From owner-freebsd-hackers@FreeBSD.ORG Wed Feb 17 20:49:26 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8F9D9106566B for ; Wed, 17 Feb 2010 20:49:26 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 624558FC1D for ; Wed, 17 Feb 2010 20:49:26 +0000 (UTC) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id 14E6846B06; Wed, 17 Feb 2010 15:49:26 -0500 (EST) Received: from jhbbsd.localnet (smtp.hudson-trading.com [209.249.190.9]) by bigwig.baldwin.cx (Postfix) with ESMTPA id 428038A021; Wed, 17 Feb 2010 15:49:25 -0500 (EST) From: John Baldwin To: freebsd-hackers@freebsd.org Date: Wed, 17 Feb 2010 14:13:56 -0500 User-Agent: KMail/1.12.1 (FreeBSD/7.2-CBSD-20100120; KDE/4.3.1; amd64; ; ) References: <291941b81002150321w7b0479beo1c6fec39ef6a7922@mail.gmail.com> In-Reply-To: <291941b81002150321w7b0479beo1c6fec39ef6a7922@mail.gmail.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201002171413.56920.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1 (bigwig.baldwin.cx); Wed, 17 Feb 2010 15:49:25 -0500 (EST) X-Virus-Scanned: clamav-milter 0.95.1 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-1.4 required=4.2 tests=AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on bigwig.baldwin.cx Cc: Shrikanth Kamath Subject: Re: Ktrace'ing kernel threads X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 17 Feb 2010 20:49:26 -0000 On Monday 15 February 2010 6:21:40 am Shrikanth Kamath wrote: > Can ktrace trace another kernel thread which has roughly the semantics as > below, right now it > does not hit any of the designated interesting points that ktrace is built > for, but what if I could define those, > will ktrace still allow tracing another kernel thread? > > thread(client_info) > { > ... > ... > build_msg(client_info); /* this will malloc a mbuf and fill the data in > it */ > ... > sosend(client_info); > } > > I want to time the entry/return of build_msg, and the time sosend, dump > client_info (some specific fields). It is probably easier to do this with DTrace (albeit possibly with more overhead). You can ktrace a kthread fine, but you would need to write your own ktrace hooks (and record parser for kdump) which would take a bit longer than a D script with DTrace. -- John Baldwin