Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933673AbZINVHg (ORCPT ); Mon, 14 Sep 2009 17:07:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757168AbZINVHe (ORCPT ); Mon, 14 Sep 2009 17:07:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:61215 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757166AbZINVHe (ORCPT ); Mon, 14 Sep 2009 17:07:34 -0400 Message-ID: <4AAEB149.2070300@redhat.com> Date: Mon, 14 Sep 2009 17:10:33 -0400 From: Masami Hiramatsu User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.1) Gecko/20090814 Fedora/3.0-2.6.b3.fc11 Thunderbird/3.0b3 MIME-Version: 1.0 To: Frederic Weisbecker CC: Steven Rostedt , Ingo Molnar , lkml , Ananth N Mavinakayanahalli , Andi Kleen , Christoph Hellwig , "Frank Ch. Eigler" , "H. Peter Anvin" , Jason Baron , Jim Keniston , "K.Prasad" , Lai Jiangshan , Li Zefan , Peter Zijlstra , Srikar Dronamraju , Tom Zanussi , systemtap , DLE Subject: Re: [PATCH tracing/kprobes 0/7] tracing/kprobes: kprobe-based event tracer update and perf support References: <20090910235258.22412.29317.stgit@dhcp-100-2-132.bos.redhat.com> <20090911013332.GB16396@nowhere> <4AAA74D2.9060203@redhat.com> <20090914025949.GB14306@nowhere> <4AAE7A5D.8010503@redhat.com> <20090914205250.GG6045@nowhere> In-Reply-To: <20090914205250.GG6045@nowhere> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2182 Lines: 77 Frederic Weisbecker wrote: > On Mon, Sep 14, 2009 at 01:16:13PM -0400, Masami Hiramatsu wrote: >> Frederic Weisbecker wrote: >>> On Fri, Sep 11, 2009 at 12:03:30PM -0400, Masami Hiramatsu wrote: >>>> Frederic Weisbecker wrote: >>>>> May be another step in the todo-list that would be nice: define the format >>>>> for a type. Like it's done from ftrace events. >>>> >>>> Thanks! >>>> >>>> BTW, I'm not sure what the type means. Each event already has its own >>>> event ID and event_call. Could you tell me which part of ftrace I should >>>> refer to ? >>>> >>> >>> >>> Actually I meant the format for a field. >>> Say you define filename=arg1, it would be nice to have >>> >>> print "%s", filename >>> >>> in the format file. >> >> Ah, indeed. It is better to support 'type' casting for each argument. >> I think type casting can be done as below syntax. >> >> NAME=ARG:TYPE >> e.g. >> jiffies64=@jiffies64:u64 >> message=%ax:str >> > > > Yeah looks good! > > > >>> Hmm, now that I think about it, we can't dereference an array...for now :-) >> >> :-) >> BTW, currently, an entry of the array can be shown, e.g. +10(sa). >> Hmm, for more complex dereference(e.g. accessing a->b[a->c]), it might need >> another dereferencing syntax(e.g. "sa[16][sa[8]]"), or >> just allow to use braces(e.g. "+(+8(sa))(+16(sa))"). > > > Well, that may be too much complexity. > I guess if we want multi level dereference, say you want a->b->c > it should be sufficient to probe the point where b->c gets it's > value (if any). > > But it would be nice to fetch a range: sa[begin:end] > Or at least just giving the length of the range. Hmm, I think it is better to treat the range as a type, because we don't know how to express each entry without the type. NAME=ARG:TYPE[LEN] e.g. regs=sa:u64[16] Thank you, -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America), Inc. Software Solutions Division e-mail: mhiramat@redhat.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/