Re: [RFC PATCH 2/5] tracing/events: nicer print format for parsing

From: Christoph Hellwig
Date: Wed Jun 10 2009 - 05:48:35 EST


On Tue, Jun 09, 2009 at 09:22:01PM +0200, Frederic Weisbecker wrote:
> But I wonder if the above new language is not breaking the charm
> of the TRACE_EVENT(), which charm is that it's easy to implement (hopefully).
>
> Everyone knows the printk formats. And I guess this new thing is easy and
> quick to learn. But because it's a new unknown language, the TRACE_EVENT
> will become less readable, less reachable for newcomers in TRACE_EVENT.

I must also say I don't particularly like it. printk is nice and easy
an everybody knows it, but it's not quite flexible enough as we might
have to do all kinds of conversions on the reader side. What might be
a better idea is to just have C function pointer for output conversions
that could be put into the a file in debugfs and used by the binary
trace buffer reader. Or maybe not as we would pull in too many
depenencies.

I think we should go with the printk solution for 2.6.31 and use the
full development cycle for 2.6.32 to come up with something better.

As soon as a couple of large subsystems use the even tracer we also
have a broader base examples to see how new syntax works on them.

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