\section{Performance monitoring}
\label{sect:monitoring}

This section describes various tools that are available to
monitor and debug the performance of EvtGen.

\subsection{Efficiency}
\label{sect:mon_eff}

One, of many, possible reason for the generator to run slowly is that
the maximum probability, against which the acceptance-rejection
method is applied, is to high. This means that the efficiency for
accepting an event is low. Diagnostics of this can be studied by 
setting the environment variable ``EVTINFO''. At the end of the
job a summary will then be printed out which gives the number of
times each decay model was invoked, the efficiency for accepting
the decay and the ratio of the largest probability in the sample
that was generated to the maximum probability. Optimal running
condition wants to maximize both of these.