Performance Profiling
---------------------

Code profiling is implemented through a few macros in ntopng, those macros can
be enabled by uncommenting the line below in include/ntop_defines.h

  #define PROFILING

In order to record the time a block of code takes to execute, you need to use the
PROFILING_SECTION_ENTER and PROFILING_SECTION_EXIT macros to create sections.
Example:

  PROFILING_SECTION_ENTER(<label>, <section id>)
  sleep (1);
  PROFILING_SECTION_EXIT(<section id>)

Each section requires a label (char *) and a unique id (uint).
The section id is an index in an array of sections. The number of sections
should be defined with PROFILING_DECLARE(<num>), see for example 
include/NetworkInterface.h.
Example:

  PROFILING_DECLARE(32);

In order to print the time (ticks) a section takes, you should use the
PROFILING_SECTION_AVG(<section id>, <iterations>) macro, providing the
section id and the number of iterations (number of times the section
has been traversed).
See for example NetworkInterface::~NetworkInterface() in src/NetworkInterface.cpp
Example:

  for (i = 0; i < PROFILING_NUM_SECTIONS; i++) {
    if (PROFILING_SECTION_LABEL(i) != NULL)
      ntop->getTrace()->traceEvent(TRACE_NORMAL, "[PROFILING] Section #%d '%s': AVG %llu ticks",
        i, PROFILING_SECTION_LABEL(i), PROFILING_SECTION_AVG(i, n));
  }