Re: Login time

[Federico Mena Quintero <federico ximian com>]

El jue, 12-04-2007 a las 14:02 +0100, John Berthels escribi� On 11/04/07, Federico Mena Quintero <federico ximian com> wrote:
> > I'd *love* to use a less pedestrian tool.  Does anyone know if Systemtap
> > is mature enough for this?  We'd need to say, "tell me every time
> > <function> gets called in this process", for a bunch of processes.
> 
> Would it suffice to trigger this from an environment variable?
> 
> If the function in question is in a shared library, an LD_PRELOAD shim
> could provide this information.

For public functions, that's a very nice idea, and quite automatable.
Ltrace(1) can give you that information on a good day.

The problem is often about static functions.  Sometimes you have

void
big_ugly_public_function ()
{
   static_function_1 ();
   static_function_2 ();
   static_function_3 ();
}

and you want the timings for the static ones (which in turn call other
static functions), so that you can find the culprit.

Other times you have static functions that get used as callbacks.  You
have an idle handler that is a static function, or a thread function,
and you can't see it from outside the process unless you are a debugger.

  Federico