X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/ea4eb2d3ae5dd567ff62f88b7e61605a94ebff0e..2d75d1cbec1f1390f086522ccc8a0b3a4e645d89:/src/surf/plugins/host_load.cpp

diff --git a/src/surf/plugins/host_load.cpp b/src/surf/plugins/host_load.cpp
index 82668bd172..31ea874530 100644
--- a/src/surf/plugins/host_load.cpp
+++ b/src/surf/plugins/host_load.cpp
@@ -49,7 +49,7 @@ private:
   double current_flops     = 0;
   double computed_flops    = 0;
   double idle_time         = 0;
-  long   theor_max_flops   = 0;
+  double theor_max_flops   = 0;
   bool   was_prev_idle     = true; /* A host is idle at the beginning */
 };
 
@@ -71,27 +71,38 @@ HostLoad::~HostLoad() = default;
 void HostLoad::update()
 {
   double now = surf_get_clock();
-  if (last_updated < now) {
-    /* flops == pstate_speed * cores_being_currently_used */
-    computed_flops += (now - last_updated) * current_flops;
 
-    /* Current flop per second computed by the cpu; current_flops = k * pstate_speed_in_flops, k \in {0, 1, ..., cores}
-     * number of active cores */
-    current_flops = host->pimpl_cpu->constraint()->get_usage();
+  /* Current flop per second computed by the cpu; current_flops = k * pstate_speed_in_flops, k \in {0, 1, ..., cores}
+   * number of active cores */
+  current_flops = host->pimpl_cpu->constraint()->get_usage();
 
-    if (was_prev_idle) {
-      idle_time += (now - last_updated);
-    }
+  /* flops == pstate_speed * cores_being_currently_used */
+  computed_flops += (now - last_updated) * current_flops;
 
-    theor_max_flops += current_speed * host->getCoreCount() * (now - last_updated);
-    current_speed    = host->getSpeed();
-    last_updated     = now;
-    was_prev_idle    = (current_flops == 0);
+  if (was_prev_idle) {
+    idle_time += (now - last_updated);
   }
+
+  theor_max_flops += current_speed * host->getCoreCount() * (now - last_updated);
+  current_speed    = host->getSpeed();
+  last_updated     = now;
+  was_prev_idle    = (current_flops == 0);
 }
 
+/**
+ * WARNING: This function does not guarantee that you have the real load at any time
+ * imagine all actions on your CPU terminate at time t. Your load is then 0. Then
+ * you query the load (still 0) and then another action starts (still at time t!).
+ * This means that the load was never really 0 (because the time didn't advance) but
+ * it will still be reported as 0.
+ *
+ * So, use at your own risk.
+ */
 double HostLoad::getCurrentLoad()
 {
+  // We don't need to call update() here because it is called everytime an
+  // action terminates or starts
+  // FIXME: Can this happen at the same time? stop -> call to getCurrentLoad, load = 0 -> next action starts?
   return current_flops / static_cast<double>(host->getSpeed() * host->getCoreCount());
 }
 
@@ -104,13 +115,15 @@ double HostLoad::getIdleTime() {
 
 double HostLoad::getAverageLoad()
 {
-  return getComputedFlops() / (host->getSpeed() * host->getCoreCount() * (surf_get_clock() - last_reset));
+  if (theor_max_flops == 0) { // Avoid division by 0
+    return 0;
+  }
+
+  return computed_flops / theor_max_flops;
 }
 
 double HostLoad::getComputedFlops()
 {
-  update();
-
   return computed_flops;
 }
 
@@ -119,9 +132,14 @@ double HostLoad::getComputedFlops()
  */
 void HostLoad::reset()
 {
-  last_updated   = surf_get_clock();
-  last_reset     = surf_get_clock();
-  computed_flops = 0;
+  last_updated    = surf_get_clock();
+  last_reset      = surf_get_clock();
+  idle_time       = 0;
+  computed_flops  = 0;
+  theor_max_flops = 0;
+  current_flops   = host->pimpl_cpu->constraint()->get_usage();
+  current_speed   = host->getSpeed();
+  was_prev_idle   = (current_flops == 0);
 }
 }
 }