Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933814AbZINUwz (ORCPT ); Mon, 14 Sep 2009 16:52:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933548AbZINUwx (ORCPT ); Mon, 14 Sep 2009 16:52:53 -0400 Received: from ey-out-2122.google.com ([74.125.78.24]:15602 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933698AbZINUww (ORCPT ); Mon, 14 Sep 2009 16:52:52 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=G+DRzRdn6lwElIaTijV3Crwr+HCqyDXe3hzuTGP+1bwwsuTEuS68l7YYAUbWcPX50p VrhUJvTQzMFZT3d5qTSRsVfgMc1kljM5G5qW3FTTOBh4YvqLwH3UmWYEBnkKz9DBCfOy Fm+DrzQ+xf39n1wUrkXA5maZnu5etNozj+4Go= Date: Mon, 14 Sep 2009 22:52:51 +0200 From: Frederic Weisbecker To: Masami Hiramatsu 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 Message-ID: <20090914205250.GG6045@nowhere> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4AAE7A5D.8010503@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1779 Lines: 58 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. -- 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/