From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17833 invoked by alias); 5 Jul 2008 18:05:23 -0000 Received: (qmail 17826 invoked by uid 22791); 5 Jul 2008 18:05:22 -0000 X-Spam-Status: No, hits=-2.6 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from e28smtp03.in.ibm.com (HELO e28esmtp03.in.ibm.com) (59.145.155.3) by sourceware.org (qpsmtpd/0.31) with ESMTP; Sat, 05 Jul 2008 18:04:57 +0000 Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by e28esmtp03.in.ibm.com (8.13.1/8.13.1) with ESMTP id m65I4ptQ005880 for ; Sat, 5 Jul 2008 23:34:51 +0530 Received: from d28av01.in.ibm.com (d28av01.in.ibm.com [9.184.220.63]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v9.0) with ESMTP id m65I4UAx1261620 for ; Sat, 5 Jul 2008 23:34:30 +0530 Received: from d28av01.in.ibm.com (loopback [127.0.0.1]) by d28av01.in.ibm.com (8.13.1/8.13.3) with ESMTP id m65I4ott005969 for ; Sat, 5 Jul 2008 23:34:51 +0530 Received: from in.ibm.com ([9.124.212.58]) by d28av01.in.ibm.com (8.13.1/8.12.11) with ESMTP id m65I4ktk005948 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sat, 5 Jul 2008 23:34:49 +0530 Date: Sat, 05 Jul 2008 18:05:00 -0000 From: "K.Prasad" To: Christoph Hellwig Cc: Peter Zijlstra , Theodore Tso , ksummit-2008-discuss@lists.linux-foundation.org, Roland McGrath , systemtap@sources.redhat.com Subject: Re: [Ksummit-2008-discuss] DTrace Message-ID: <20080705180432.GA6077@in.ibm.com> Reply-To: prasad@linux.vnet.ibm.com References: <20080630192533.GE21660@redhat.com> <20080630201031.GF7988@mit.edu> <20080630204219.GA6631@redhat.com> <20080701024140.GB28143@mit.edu> <20080701070746.C6DAD15420E@magilla.localdomain> <20080701101507.GB22717@mit.edu> <20080701200632.6790A1541F5@magilla.localdomain> <20080701231327.GA5829@mit.edu> <1215251049.6320.15.camel@lappy.programming.kicks-ass.net> <20080705100536.GA18534@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080705100536.GA18534@lst.de> User-Agent: Mutt/1.5.18 (2008-05-17) X-IsSubscribed: yes Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2008-q3/txt/msg00051.txt.bz2 On Sat, Jul 05, 2008 at 12:05:36PM +0200, Christoph Hellwig wrote: > On Sat, Jul 05, 2008 at 11:44:09AM +0200, Peter Zijlstra wrote: > > Also, it would be really great if you could write probes in regular C, > > some pseudo C language just messes up my mind. > > You can write probes in plain C, in fact I do this all the time. what's > missing is a nice and easy to use channel to get the traces to userspace > and interpret them, and helper for poking at kernel data structures. > As you might be aware the "trace" interface which is part of the -mm tree was meant to satisfy such needs. Moreover, an enhancement over the "trace" interface introduced in the form of relay_printk() [for string output] and relay_dump() [for binary output] was meant to give the user a printk()-like interface, but with the advantages of using relay (such as per-cpu buffers) is still waiting for acceptance and use-cases (Refer http://lkml.org/lkml/2008/5/28/212). A typical example illustrating the brevity of the code when using the relay_printk() interface can be found in the samples/trace/fork_new_trace.c file in the patch. Thanks, K.Prasad