Re: [PATCH 02/11] tracing: Introduce TRACE_EVENT_INJECT

[Frederic Weisbecker <fweisbec@gmail.com>]

On Sat, Feb 06, 2010 at 08:19:30AM -0500, Steven Rostedt wrote:
> On Sat, 2010-02-06 at 13:20 +0100, Frederic Weisbecker wrote:
> 
> > I agree with you that creating a new trace event macro is a bit
> > insane. ftrace.h is already a nightmare. I just thought that
> > having the injector set inside the same macro that the synchronous
> > event is defined helped to make it clear about its nature: that
> > it needs a secondary async catch up thing.
> > 
> > But a register_event_injector thing will work too, we probably
> > better want that, given the maintainance pain otherwise.
> 
> We can add a register_event_injector later. For now, why not just add
> the TRACE_EVENT() and then hook to it in perf using the normal
> tracepoint mechanism.
> 
> You could add some macro around the trace_init_lock_class() call that
> would facilitate finding all the locks you need. This would probably be
> a bit more straight forward than to overload TRACE_EVENT() again.



I'm not sure what you mean by that.


 
> > 
> > I really would like to make something useful for everyone, could
> > you tell me more about johill needs?
> 
> Well, basically he needed a way to cause polling to happen using an
> event. From what I understood, the polling called the trace point. Just
> enabling the trace point did nothing because the polling did not take
> place. I thought about ways to enable this command when the trace point
> was enabled. But in the end, it was specific to a driver and another
> debugfs file seemed a better fit to initiate it.


Ok, thanks.