Re: [Patch RFC 0/2] tracing: allow disabling compilation of specific trace systems
From: Steven Rostedt
Date: Thu Jun 25 2015 - 18:26:00 EST
On Thu, 25 Jun 2015 23:41:17 +0300
Tal Shorer <tal.shorer@xxxxxxxxx> wrote:
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.
> On Sat, Jun 20, 2015 at 11:21 PM, Tal Shorer <tal.shorer@xxxxxxxxx> 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
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