Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756590AbZFJB6L (ORCPT ); Tue, 9 Jun 2009 21:58:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754489AbZFJB56 (ORCPT ); Tue, 9 Jun 2009 21:57:58 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:63555 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752587AbZFJB56 (ORCPT ); Tue, 9 Jun 2009 21:57:58 -0400 Message-ID: <4A2F1376.7040500@cn.fujitsu.com> Date: Wed, 10 Jun 2009 09:59:18 +0800 From: Lai Jiangshan User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: Steven Rostedt CC: Frederic Weisbecker , linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Minchan Kim , Mel Gorman , Christoph Hellwig , Rik van Riel , Pekka Enberg , Peter Zijlstra , Theodore Tso , Mathieu Desnoyers , Zhaolei , KOSAKI Motohiro , Jason Baron , Jiaying Zhang Subject: Re: [RFC PATCH 2/5] tracing/events: nicer print format for parsing References: <20090609014534.790466803@goodmis.org> <20090609014746.481457542@goodmis.org> <20090609192159.GD6057@nowhere> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2506 Lines: 60 Steven Rostedt wrote: > On Tue, 9 Jun 2009, Frederic Weisbecker wrote: >> >>> The language that is added by this patch is of the following: >>> >>> * FMT := constant string FMT | COMMAND FMT | empty >>> * COMMAND := | | | >>> * >>> * TYPE := int | hex | ptr | string | strarray >>> * FIELD := defined by the event structure >>> * MASKS := MASK=NAME,MASKS | MASK=NAME >>> * MASK := the bit mask to match >>> * DELIM := delimiter to separate the fields. None and ':' are both allowed >>> * SYMBOLS := SYM=NAME,SYMBOLS | SYM=NAME >>> * SYM := the symbol value to test against >>> * TRUE := print when field is non zero >>> * FALSE := print when field is zero or NULL >>> * NAME := the name to write when a match is found >>> * >>> * A '\<' would print '<' >> >> But I wonder if the above new language is not breaking the charm >> of the TRACE_EVENT(), which charm is that it's easy to implement (hopefully). >> >> Everyone knows the printk formats. And I guess this new thing is easy and >> quick to learn. But because it's a new unknown language, the TRACE_EVENT >> will become less readable, less reachable for newcomers in TRACE_EVENT. > > I tried to avoid this too, but when I started writing a tool in C that > would parse the format file, I found that the printf was horrible. > > Note, I will still keep the TP_printk() macro, that will not change. The > new macro is TP_FORMAT() that preforms the tags. Thus, if you really want > it to print out, you can use TP_printk, but the user space tools that read > the binary will not know how to read it unless the printk is simple. > > I really want to keep this language simple. If anyone has any better > ideas, I'm all for it. > > I barfed when I saw this in irq_handler_entry: > > print fmt: "irq=%d handler=%s", REC->irq, (char *)((void *)REC + REC->__data_loc_name) > I barfed too when I saw this. Introducing a new format is very meaningful. And this print format looks well. Good Work! I'm trying to write user-space tools. Could you tell me your tools' developing status? And the aim of these tools? Will it be public? I'm wandering whether I should stop this trying. Lai. -- 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/