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Subject: Re: [RFC][PATCH 0/2] tracing: Have trace_printk()s in the events/
 directory
From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
        Andrew Morton <akpm@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
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        Darren Hart <dvhart@linux.intel.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        "jason.wessel" <jason.wessel@windriver.com>,
        "Ted Ts'o" <tytso@mit.edu>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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Date: Thu, 18 Nov 2010 11:41:06 +0100
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On Wed, 2010-11-17 at 22:58 -0500, Steven Rostedt wrote:
> For example, I added a trace_printk() in kernel/sched.c at line 2180
> and it creates:
> 
> # ls /debug/tracing/events/printk/kernel/sched.c/2180/
> enable  format
> 
> The format is the printk format:
> 
> # cat /debug/tracing/events/printk/kernel/sched.c/2180/format 
> "migrate task %s:%d"

*groan*, so you're creating a tracepoint per instance?

That's going to be massive pain for perf.. I really don't see the point
in splitting all that out.