loba_bulk.cpp

   1 #include <xbt/log.h>
   2 #include <math.h>
   3
   4 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(loba);
   5
   6 #include "loba_bulk.h"
   7
   8 void loba_bulk::load_balance()
   9 {
  10         float myLoad = get_load();
  11
  12         unsigned NbNwMinLoad = 0;
  13         unsigned NbNwLowerLoad = 0;
  14         unsigned NbNeighbours = pneigh.size();
  15
  16         double *S = new double[NbNeighbours];
  17         for (unsigned i = 0; i < NbNeighbours; i++)
  18                 S[i] = 0.0;
  19         //What is the minimum and maximum load under myLoad?
  20         float minLoad = myLoad;
  21         for (unsigned i = 0; i < NbNeighbours; i++) {
  22                 if (pneigh[i]->get_load() < minLoad) {
  23                         minLoad = pneigh[i]->get_load();
  24                 }
  25                 if (pneigh[i]->get_load() < myLoad) {
  26                         NbNwLowerLoad++;
  27                 }
  28         }
  29         for (unsigned i = 0; i < NbNeighbours; i++)
  30                 if (pneigh[i]->get_load() == minLoad)
  31                         NbNwMinLoad++;
  32
  33         float maxLoad = minLoad;
  34         for (unsigned i = 0; i < NbNeighbours; i++) {
  35                 if (pneigh[i]->get_load() > minLoad && pneigh[i]->get_load() < myLoad)
  36                         if (maxLoad < pneigh[i]->get_load())
  37                                 maxLoad = pneigh[i]->get_load();
  38         }
  39
  40         double alpha = 0.0;
  41
  42         if (NbNwLowerLoad && NbNwMinLoad < NbNwLowerLoad) //There is one or many neighbors with minimum load but not all neighbors have minimum load
  43                 alpha = (1. / ((double) NbNwMinLoad + 2));
  44         if (NbNwMinLoad == NbNwLowerLoad) //All neighbors have minimum load
  45                 alpha = (1. / ((double) NbNwMinLoad + 1));
  46         float myS = 0.;
  47         //There exist underloaded neighbors
  48         if (NbNwMinLoad && myLoad != 0.0) {
  49                 for (unsigned i = 0; i < NbNeighbours; i++) {
  50                         if (pneigh[i]->get_load() == minLoad) {
  51                                 S[i] = floor(alpha * (myLoad - minLoad));
  52                                 myS +=  S[i];
  53                         } else {
  54                                 if (pneigh[i]->get_load() < myLoad) {
  55                                         S[i] = floor(alpha * (myLoad - pneigh[i]->get_load()));
  56                                         myS +=  S[i];
  57                                 }
  58                         }
  59                 }
  60                 //Check assumption 4.2 (b) page 520
  61                 bool HaveToCorrectS = false;
  62                 for (unsigned i = 0; i < NbNeighbours; i++) {
  63                         if (pneigh[i]->get_load() < myLoad) { //
  64                                 //Condition 4.6
  65                                 if ((myLoad - myS) < (pneigh[i]->get_load() + S[i])) {
  66                                         HaveToCorrectS = true;
  67                                 }
  68                         }
  69                 }
  70                 if (HaveToCorrectS) {
  71                                 for (unsigned i = 0; i < NbNeighbours; i++) {
  72                                         while (((myLoad - myS) < pneigh[i]->get_load() + S[i]) && (S[i] > 0)) {
  73                                                 myS -= 1.0;
  74                                                 S[i] -= 1.0;
  75                                         }
  76                                 }
  77                 }
  78         }//End there are underloaded neighbors;
  79         for (unsigned i = 0 ; i < NbNeighbours ; i++) {
  80                 send(pneigh[i], S[i]);
  81                 XBT_DEBUG("sent to %s", pneigh[i]->get_name());
  82         }
  83
  84         delete[] S;
  85 }
  86
  87 // Local variables:
  88 // mode: c++
  89 // End: