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Date: Mon, 29 Jun 2009 13:19:02 +0200
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Li Zefan <lizf@cn.fujitsu.com>, Steven Rostedt <rostedt@goodmis.org>,
       LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] tracing/fastboot: document the need of initcall_debug
Message-ID: <20090629111901.GB6265@nowhere>
References: <4A48735E.9050002@cn.fujitsu.com> <20090629082152.GA2921@elte.hu> <4A488304.9000104@cn.fujitsu.com> <20090629091422.GA9724@elte.hu>
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On Mon, Jun 29, 2009 at 11:14:22AM +0200, Ingo Molnar wrote:
> 
> * Li Zefan <lizf@cn.fujitsu.com> wrote:
> 
> > Ingo Molnar wrote:
> > > * Li Zefan <lizf@cn.fujitsu.com> wrote:
> > > 
> > >> To use boot tracer, one should pass initcall_debug as well as
> > >> ftrace=initcall to the command line.
> > > 
> > > I think both should be auto-enabled if BOOT_TRACER is enabled, for 
> > > ease of use - agreed?
> > 
> > If both are auto-enabled, we'll always do boot tracing. But we 
> > want BOOT_TRACER to be enabled and only enable boot tracing when 
> > it's needed.
> > 
> > But maybe we can make ftrace=initcall implies initcall_debug=1?
> 
> That's reasonable indeed.
> 
> 	Ingo

Yeah.

Although I wonder if this tracer is still useful.
It was first written to debug fastboot, to get more
than the initcall_debug output, ie: the scheduling
events but now I guess the latter is not useful
anymore. And using initcall_debug already does the
job of printing the initcall events.

What do you think?