+\section options_smpi Configuring SMPI
+
+The SMPI interface provides several specific configuration items.
+These are uneasy to see since the code is usually launched through the
+\c smiprun script directly.
+
+\subsection options_smpi_bench Automatic benchmarking of SMPI code
+
+In SMPI, the sequential code is automatically benchmarked, and these
+computations are automatically reported to the simulator. That is to
+say that if you have a large computation between a \c MPI_Recv() and a
+\c MPI_Send(), SMPI will automatically benchmark the duration of this
+code, and create an execution task within the simulator to take this
+into account. For that, the actual duration is measured on the host
+machine and then scaled to the power of the corresponding simulated
+machine. The variable \b smpi/running_power allows to specify the
+computational power of the host machine (in flop/s) to use when
+scaling the execution times. It defaults to 20000, but you really want
+to update it to get accurate simulation results.
+
+When the code is constituted of numerous consecutive MPI calls, the
+previous mechanism feeds the simulation kernel with numerous tiny
+computations. The \b smpi/cpu_threshold item becomes handy when this
+impacts badly the simulation performance. It specify a threshold (in
+second) under which the execution chunks are not reported to the
+simulation kernel (default value: 1e-6). Please note that in some
+circonstances, this optimization can hinder the simulation accuracy.
+
+\subsection options_smpi_timing Reporting simulation time
+
+Most of the time, you run MPI code through SMPI to compute the time it
+would take to run it on a platform that you don't have. But since the
+code is run through the \c smpirun script, you don't have any control
+on the launcher code, making difficult to report the simulated time
+when the simulation ends. If you set the \b smpi/display_timing item
+to 1, \c smpirun will display this information when the simulation ends. \verbatim
+Simulation time: 1e3 seconds.
+\endverbatim
+
+
+