[energy] react sainly when the host speed is 0

(fix #44)

diff --git a/src/surf/plugins/energy.cpp b/src/surf/plugins/energy.cpp
index 8f5a2ba..0f7f72c 100644 (file)
--- a/src/surf/plugins/energy.cpp
+++ b/src/surf/plugins/energy.cpp
@@ -63,9 +63,15 @@ using simgrid::energy::surf_energy;
 
 /* Computes the consumption so far.  Called lazily on need. */
 static void update_consumption(simgrid::surf::Host *host, HostEnergy *host_energy) {
-       double cpu_load = lmm_constraint_get_usage(host->p_cpu->getConstraint()) / host->p_cpu->m_speedPeak;
        double start_time = host_energy->last_updated;
        double finish_time = surf_get_clock();
+       double cpu_load;
+       if (host->p_cpu->m_speedPeak == 0)
+               // Some users declare a pstate of speed 0 flops (eg to model boot time).
+               // We consider that the machine is then fully loaded. That's arbitrary but it avoids a NaN
+               cpu_load = 1;
+       else
+               cpu_load = lmm_constraint_get_usage(host->p_cpu->getConstraint()) / host->p_cpu->m_speedPeak;
 
        double previous_energy = host_energy->total_energy;