Re: [PATCH] tracing: add trace console

Johannes Berg
2011-11-16T15:17:38Z

On Wed, 2011-11-16 at 10:10 -0500, Christoph Hellwig wrote:
> On Wed, Nov 16, 2011 at 11:18:48AM +0100, Johannes Berg wrote:
> > From: Johannes Berg <johannes.berg@intel.com>
> >
> > As described in the Kconfig entry, logging printk
> > output is useful to correlate (existing) printk
> > debugging with (existing) tracing. The easiest way
> > to achieve this is to register a console that just
> > calls trace_printk(), which this module does.
>
> I'd much prefer if we could have it built in all the time, but had a
> way to enable it at runtime, just like all the "real" tracepoints.

That's possible, basically adding a tracepoints to printk -- that would
even catch everything and not require setting the console level (which
has its advantages too since other consoles might be slow).

It's a completely different thing though. I did it this way because it
was trivial to do out of tree for a quick test I was doing yesterday.
Doing it the other way is obviously more intrusive in core code.

johannes