Update core stats.

        Stats is a dict (with both physical and log cpu number) instead of a integer.

def update(self):
        """Update core stats.

        Stats is a dict (with both physical and log cpu number) instead of a integer.
        """
        # Init new stats
        stats = self.get_init_value()

        if self.input_method == 'local':
            # Update stats using the standard system lib

            # The psutil 2.0 include psutil.cpu_count() and psutil.cpu_count(logical=False)
            # Return a dict with:
            # - phys: physical cores only (hyper thread CPUs are excluded)
            # - log: logical CPUs in the system
            # Return None if undefine
            try:
                stats["phys"] = psutil.cpu_count(logical=False)
                stats["log"] = psutil.cpu_count()
            except NameError:
                self.reset()

        elif self.input_method == 'snmp':
            # Update stats using SNMP
            # http://stackoverflow.com/questions/5662467/how-to-find-out-the-number-of-cpus-using-snmp
            pass

        # Update the stats
        self.stats = stats

        return self.stats