Re: [PATCH 1/1] ftrace: fix dynamic ftrace filter reset issue
From: Steven Rostedt
Date: Sat Mar 24 2012 - 10:55:40 EST
On Sat, 2012-03-24 at 09:47 +0530, Rajesh Bhagat wrote:
> Hi Steven,
> Thanks for the reply.
> I was wondering, why would a user reset the trace __explicitly__
> without even using it.
> That is why i created a patch for it.
> >> /debug/tracing # echo function > current_tracer
user starts using tracer
> >> /debug/tracing # cat trace <------ Not performed
> >> /debug/tracing # echo schedule > set_ftrace_filter
> >> /debug/tracing # echo function > current_trace
> >> /debug/tracing # cat trace <------- Only this is performed
Why the first "echo function"? That means you just started using the
tracer. You can (and should) do:
# echo schedule > set_ftrace_filter
# echo function > current_tracer
This IIRC is the documented way of using it.
That said, I may consider taking the patch, as another way of resetting
the tracer. I have to see what workflows it will affect first.
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