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Date: Wed, 25 Feb 2009 08:37:40 -0500
From: Theodore Tso <tytso@mit.edu>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>, linux-kernel@vger.kernel.org,
       Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
       Peter Zijlstra <peterz@infradead.org>,
       Frederic Weisbecker <fweisbec@gmail.com>,
       Arjan van de Ven <arjan@infradead.org>, Pekka Paalanen <pq@iki.fi>,
       Arnaldo Carvalho de Melo <acme@redhat.com>,
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       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
       Jens Axboe <jens.axboe@oracle.com>,
       Masami Hiramatsu <mhiramat@redhat.com>,
       Steven Rostedt <srostedt@redhat.com>
Subject: Re: [PATCH 2/4] tracing: add event trace infrastructure
Message-ID: <20090225133740.GF7064@mit.edu>
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	Jens Axboe <jens.axboe@oracle.com>,
	Masami Hiramatsu <mhiramat@redhat.com>,
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References: <20090225025608.956691460@goodmis.org> <20090225025753.798204550@goodmis.org> <20090224194548.3effb746.akpm@linux-foundation.org>
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On Tue, Feb 24, 2009 at 07:45:48PM -0800, Andrew Morton wrote:
> echo sched_wakeup > /debug/tracing/set_event
> echo sched_wakeup > /debug/tracing/clear_event
> echo 1 > /debug/tracing/clear_all_events

>>From a usability point of view, I'd prefer this as well.  It's only
two extra files, but it means that filenames in /deb/tracing is
self-documenting, which is a good thing.  Otherwise, it's really not
obvious that "echo !event > /debug/tracing/set_event" will disable the
event, and it's *especially* not obvious "echo > /debug/tracing/set_event"
will disable all events.

It's also a tad bit too easy to typo "echo > /debug/tracing/set_event"
by editing command history, and hitting return a bit too soon after
clearing out the previous event name but before you manage to type the
new event name.

						- Ted