There is a debugging console included with Smarty. The console informs you
  of all the
  included templates,
  assigned variables and
  config
  file variables for the current invocation of the template. A template file
  named debug.tpl is included with the distribution of
  Smarty which controls the formatting of the console.
  
  Set  $debugging
  to TRUE in Smarty, and if needed set 
  $debug_tpl to the template resource path to
  debug.tpl (this is in 
  SMARTY_DIR by default).
  When you load the page, a Javascript console window will pop up
  and give you the names of all the included templates and assigned variables
  for the current page.
To see the available variables for a particular
  template, see the 
  {debug} template function.
  To disable the debugging console, set
  $debugging to
  FALSE. You can also temporarily turn on the debugging console by putting
  SMARTY_DEBUG in the URL if you enable this option with
  $debugging_ctrl
  .
 
   The debugging console does not work when you use the
   fetch()
   API, only when using  
   display().
   It is a set of javascript statements added
   to the very bottom of the generated template. If you do not like javascript,
   you can edit the debug.tpl template to format the output
   however you like.  Debug data is not cached and debug.tpl
    info is not included in the output of the debug console.
  
The load times of each template and config file are in seconds, or fractions thereof.
See also troubleshooting.