Re: [Patch RFC 0/2] tracing: allow disabling compilation of specific trace systems

[Steven Rostedt <rostedt@goodmis.org>]

On Thu, 25 Jun 2015 23:41:17 +0300
Tal Shorer <tal.shorer@gmail.com> wrote:

> ping?

I'm planning on looking at this after I've finished everything for the
merge window. This came over the weekend (always a bad time), and the
merge window opened. All new code needs to take a backseat while the
merge window is opened.

I may not get to this till next week. Feel free to ping me again then.

-- Steve


> 
> On Sat, Jun 20, 2015 at 11:21 PM, Tal Shorer <tal.shorer@gmail.com> wrote:
> > Currently, enabling CONFIG_TRACING on a system comes as all-or-nothing: either
> > tracepoints for all subsystems are compiled (with CONFIG_TRACING) or none of
> > them do (without it).
> >
> > This caused me an unacceptable performance penalty (obviously SOME penalty was
> > expected, but not one so severe) which made me revert the changes in
> > configuration.
> >
> > The first patch in this series modifies the files that actually define the
> > tracepoint to look for a preprocessor macro NOTRACE and define nops (as if
> > CONFIG_TRACING was not set) instead of them.
> >
> > The second patch provides an example of how I see this working, with the gpio
> > subsystem as the example for absolutely no reason.
> > If this idea is deemed worth the time by the community, I'll create patches for
> > the other subsystems.
> >
> > Tal Shorer (2):
> >   tracing: allow disabling compilation of specific trace systems
> >   tracing: gpio: add Kconfig option for enabling/disabling trace events
> >
> >  drivers/gpio/Kconfig         | 6 ++++++
> >  include/linux/tracepoint.h   | 6 +++---
> >  include/trace/define_trace.h | 2 +-
> >  include/trace/events/gpio.h  | 4 ++++
> >  4 files changed, 14 insertions(+), 4 deletions(-)
> >
> > --
> > 2.2.2
> >