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Subject: RE: [PATCH 3/6] pstore: Add persistent function tracing
From: Steven Rostedt <rostedt@goodmis.org>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Anton Vorontsov <anton.vorontsov@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
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On Fri, 2012-06-15 at 21:40 +0000, Luck, Tony wrote:
> > We store the log in a binary format and then decode it at read time.
> 
> What are the advantages of this compared to creating the human
> readable text and saving a blob of text?

With function tracing the impact to performance is tremendous. Just
recording two long words is a 130% hit to performance. Now multiply that
to recording strings.

> 
> What does this "binary format" look like?  Will it ever change?
> Remember that we may reboot to a different kernel - so we have
> to be really sure that the newer (or older) version can do the decode.

Good question.

-- Steve


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