Re: [PATCH 09/15] xen/trace: add tlb flush tracepoints

Steven Rostedt
2011-06-24T02:00:06Z

On Thu, 2011-06-23 at 15:58 -0700, Jeremy Fitzhardinge wrote:

> > If you really need something like this, maybe I'll add a
> > DEFINE_EVENT_NOARGS() that will not require arguments and can eliminate
> > a lot of code that TRACE_EVENT() adds.
>
> If you like, but only if you think its worth the effort. The empty
> string thing is a bit of an ugly hack, but its not like it makes a mess
> everywhere.

The problem I have is not the ugliness, but more of the wasted code that
is generated to do nothing. The TRACE_EVENT() generates lots of helper
functions that are unique to handle different events. The fact that we
have no args is generating code that does a lot of nothing. Every
TRACE_EVENT() can create 5k of code/data. This is why I advocate the
DEFINE_TRACE_CLASS() and DEFINE_EVENT() because it reuses a lot of the
code.

If we had a NOARGS event that was just a marker, then we could eliminate
most of the helper functions for these kinds of trace points.

-- Steve