X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/84b49f68eeec8692daf7ae6ed18d5c2bb7940ba2..f01580e0ccb84c36906cb6be929b5c9b784c1cc1:/src/surf/surf_routing_cluster_fat_tree.cpp

diff --git a/src/surf/surf_routing_cluster_fat_tree.cpp b/src/surf/surf_routing_cluster_fat_tree.cpp
index 01d40f035a..e68b89c0da 100644
--- a/src/surf/surf_routing_cluster_fat_tree.cpp
+++ b/src/surf/surf_routing_cluster_fat_tree.cpp
@@ -1,229 +1,529 @@
-#include "surf_routing_cluster_fat_tree.hpp"
+#include <cstdlib>
+
+#include <map>
+#include <string>
+#include <utility>
+#include <vector>
+#include <iostream>
+
+#include "src/surf/surf_routing_private.hpp"
+#include "src/surf/surf_routing_cluster_fat_tree.hpp"
 #include "xbt/lib.h"
 
 #include <boost/algorithm/string/split.hpp>
 #include <boost/algorithm/string/classification.hpp>
 #include <iostream>
 #include <fstream>
+#include <sstream>
 
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_route_fat_tree, surf, "Routing for fat trees");
 
-AsClusterFatTree::AsClusterFatTree() : levels(0) {}
+namespace simgrid {
+namespace surf {
+
+AsClusterFatTree::AsClusterFatTree(const char*name)
+  : AsCluster(name)
+{
+  XBT_DEBUG("Creating a new fat tree.");
+}
 
 AsClusterFatTree::~AsClusterFatTree() {
-  for (unsigned int i = 0 ; i < this->nodes.size() ; i++) {
-    delete this->nodes[i];
+  for (unsigned int i = 0 ; i < this->nodes_.size() ; i++) {
+    delete this->nodes_[i];
+  }
+  for (unsigned int i = 0 ; i < this->links_.size() ; i++) {
+    delete this->links_[i];
   }
 }
 
-void AsClusterFatTree::getRouteAndLatency(RoutingEdgePtr src,
-                                          RoutingEdgePtr dst,
+bool AsClusterFatTree::isInSubTree(FatTreeNode *root, FatTreeNode *node) {
+  XBT_DEBUG("Is %d(%u,%u) in the sub tree of %d(%u,%u) ?", node->id,
+            node->level, node->position, root->id, root->level, root->position);
+  if (root->level <= node->level) {
+    return false;
+  }
+  for (unsigned int i = 0 ; i < node->level ; i++) {
+    if(root->label[i] != node->label[i]) {
+      return false;
+    }
+  }
+  
+  for (unsigned int i = root->level ; i < this->levels_ ; i++) {
+    if(root->label[i] != node->label[i]) {
+      return false;
+    }
+  }
+  return true;
+}
+
+void AsClusterFatTree::getRouteAndLatency(NetCard *src,
+                                          NetCard *dst,
                                           sg_platf_route_cbarg_t into,
                                           double *latency) {
-  // TODO
+  FatTreeNode *source, *destination, *currentNode;
+
+  std::map<int, FatTreeNode*>::const_iterator tempIter;
+  
+if (dst->getRcType() == SURF_NETWORK_ELEMENT_ROUTER || src->getRcType() == SURF_NETWORK_ELEMENT_ROUTER) return;
+
+  /* Let's find the source and the destination in our internal structure */
+  tempIter = this->computeNodes_.find(src->id());
+
+  // xbt_die -> assert
+  if (tempIter == this->computeNodes_.end()) {
+    xbt_die("Could not find the source %s [%d] in the fat tree", src->name(),
+            src->id());
+  }
+  source = tempIter->second;
+  tempIter = this->computeNodes_.find(dst->id());
+  if (tempIter == this->computeNodes_.end()) {
+    xbt_die("Could not find the destination %s [%d] in the fat tree",
+            dst->name(), dst->id());
+  }
+
+
+  destination = tempIter->second;
+  
+  XBT_VERB("Get route and latency from '%s' [%d] to '%s' [%d] in a fat tree",
+            src->name(), src->id(), dst->name(), dst->id());
+
+  /* In case destination is the source, and there is a loopback, let's get
+     through it instead of going up to a switch*/
+  if(source->id == destination->id && this->has_loopback_) {
+    xbt_dynar_push_as(into->link_list, void*, source->loopback);
+    if(latency) {
+      *latency += source->loopback->getLatency();
+    }
+    return;
+  }
+
+  currentNode = source;
+
+  // up part
+  while (!isInSubTree(currentNode, destination)) {
+    int d, k; // as in d-mod-k
+    d = destination->position;
+
+    for (unsigned int i = 0 ; i < currentNode->level ; i++) {
+      d /= this->upperLevelNodesNumber_[i];
+    }
+    k = this->upperLevelNodesNumber_[currentNode->level];
+    d = d % k;
+    xbt_dynar_push_as(into->link_list, void*,currentNode->parents[d]->upLink);
+
+    if(latency) {
+      *latency += currentNode->parents[d]->upLink->getLatency();
+    }
+
+    if (this->has_limiter_) {
+      xbt_dynar_push_as(into->link_list, void*,currentNode->limiterLink);
+    }
+    currentNode = currentNode->parents[d]->upNode;
+  }
+
+  XBT_DEBUG("%d(%u,%u) is in the sub tree of %d(%u,%u).", destination->id,
+            destination->level, destination->position, currentNode->id,
+            currentNode->level, currentNode->position);
+
+  // Down part
+  while(currentNode != destination) {
+    for(unsigned int i = 0 ; i < currentNode->children.size() ; i++) {
+      if(i % this->lowerLevelNodesNumber_[currentNode->level - 1] ==
+         destination->label[currentNode->level - 1]) {
+        xbt_dynar_push_as(into->link_list, void*,currentNode->children[i]->downLink);
+        if(latency) {
+          *latency += currentNode->children[i]->downLink->getLatency();
+        }
+        currentNode = currentNode->children[i]->downNode;
+        if (this->has_limiter_) {
+          xbt_dynar_push_as(into->link_list, void*,currentNode->limiterLink);
+        }
+        XBT_DEBUG("%d(%u,%u) is accessible through %d(%u,%u)", destination->id,
+                  destination->level, destination->position, currentNode->id,
+                  currentNode->level, currentNode->position);
+      }
+    }
+  }
 }
 
 /* This function makes the assumption that parse_specific_arguments() and
  * addNodes() have already been called
  */
-void AsClusterFatTree::create_links(sg_platf_cluster_cbarg_t cluster) {
-
-  if(this->levels == 0) {
+void AsClusterFatTree::create_links(){
+  if(this->levels_ == 0) {
     return;
   }
-  this->nodesByLevel.resize(this->levels, 0);
-  unsigned int nodesRequired = 0;
+  this->generateSwitches();
 
 
-  for (unsigned int i = 0 ; i < this->levels ; i++) {
-    int nodesInThisLevel = 1;
-      
-    for (unsigned int j = 0 ;  j < i ; j++) {
-      nodesInThisLevel *= this->upperLevelNodesNumber[j];
+  if(XBT_LOG_ISENABLED(surf_route_fat_tree, xbt_log_priority_debug)) {
+    std::stringstream msgBuffer;
+
+    msgBuffer << "We are creating a fat tree of " << this->levels_ << " levels "
+              << "with " << this->nodesByLevel_[0] << " processing nodes";
+    for (unsigned int i = 1 ; i <= this->levels_ ; i++) {
+      msgBuffer << ", " << this->nodesByLevel_[i] << " switches at level " << i;
     }
-      
-    for (unsigned int j = i+1 ; j < this->levels ; j++) {
-      nodesInThisLevel *= this->lowerLevelNodesNumber[j];
+    XBT_DEBUG("%s", msgBuffer.str().c_str());
+    msgBuffer.str("");
+    msgBuffer << "Nodes are : ";
+
+    for (unsigned int i = 0 ;  i < this->nodes_.size() ; i++) {
+      msgBuffer << this->nodes_[i]->id << "(" << this->nodes_[i]->level << ","
+                << this->nodes_[i]->position << ") ";
     }
+    XBT_DEBUG("%s", msgBuffer.str().c_str());
+  }
 
-    this->nodesByLevel[i] = nodesInThisLevel;
-    nodesRequired += nodesInThisLevel;
+
+  this->generateLabels();
+
+  unsigned int k = 0;
+  // Nodes are totally ordered, by level and then by position, in this->nodes
+  for (unsigned int i = 0 ; i < this->levels_ ; i++) {
+    for (unsigned int j = 0 ; j < this->nodesByLevel_[i] ; j++) {
+        this->connectNodeToParents(this->nodes_[k]);
+        k++;
+    }
   }
-   
-  if(nodesRequired > this->nodes.size()) {
-    surf_parse_error("There is not enough nodes to fit to the described topology."
-                     " Please check your platform description (We need %d nodes, we only got %zu)",
-                     nodesRequired, this->nodes.size());
-    return;
+  
+  if(XBT_LOG_ISENABLED(surf_route_fat_tree, xbt_log_priority_debug)) {
+    std::stringstream msgBuffer;
+    msgBuffer << "Links are : ";
+    for (unsigned int i = 0 ; i < this->links_.size() ; i++) {
+      msgBuffer << "(" << this->links_[i]->upNode->id << ","
+                << this->links_[i]->downNode->id << ") ";
+    }
+    XBT_DEBUG("%s", msgBuffer.str().c_str());
   }
 
-  // Nodes are totally ordered, by level and then by position, in this->nodes
-  int k = 0;
-  for (unsigned int i = 0 ; i < this->levels ; i++) {
-    for (unsigned int j = 0 ; j < this->nodesByLevel[i] ; j++) {
-      this->nodes[k]->level = i;
-      this->nodes[k]->position = j;
-      if(i != 0) {
-        int position, size;
-        this->getLevelPosition(i - 1, &position, &size); // TODO : check position and size ?
-        /* We create the connexions between this nodes and all its parents
-         */
-        for (unsigned int l = this->upperLevelNodesNumber[i] * j ;
-             l < this->upperLevelNodesNumber[i] * (j + 1) ; l++)
-          this->addLink(cluster, this->nodes[position + l], this->nodes[k]);
+
+}
+
+int AsClusterFatTree::connectNodeToParents(FatTreeNode *node) {
+  std::vector<FatTreeNode*>::iterator currentParentNode = this->nodes_.begin();
+  int connectionsNumber = 0;
+  const int level = node->level;
+  XBT_DEBUG("We are connecting node %d(%u,%u) to his parents.",
+            node->id, node->level, node->position);
+  currentParentNode += this->getLevelPosition(level + 1);
+  for (unsigned int i = 0 ; i < this->nodesByLevel_[level + 1] ; i++ ) {
+    if(this->areRelated(*currentParentNode, node)) {
+      XBT_DEBUG("%d(%u,%u) and %d(%u,%u) are related,"
+                " with %u links between them.", node->id,
+                node->level, node->position, (*currentParentNode)->id,
+                (*currentParentNode)->level, (*currentParentNode)->position, this->lowerLevelPortsNumber_[level]);
+      for (unsigned int j = 0 ; j < this->lowerLevelPortsNumber_[level] ; j++) {
+      this->addLink(*currentParentNode, node->label[level] +
+                    j * this->lowerLevelNodesNumber_[level], node,
+                    (*currentParentNode)->label[level] +
+                    j * this->upperLevelNodesNumber_[level]);
       }
-      k++;
+      connectionsNumber++;
+    }
+    ++currentParentNode;
+  }
+  return connectionsNumber;
+}
+
+
+bool AsClusterFatTree::areRelated(FatTreeNode *parent, FatTreeNode *child) {
+  std::stringstream msgBuffer;
+
+  if(XBT_LOG_ISENABLED(surf_route_fat_tree, xbt_log_priority_debug)) {
+    msgBuffer << "Are " << child->id << "(" << child->level << ","
+              << child->position << ") <";
+
+    for (unsigned int i = 0 ; i < this->levels_ ; i++) {
+      msgBuffer << child->label[i] << ",";
     }
+    msgBuffer << ">";
+    
+    msgBuffer << " and " << parent->id << "(" << parent->level
+              << "," << parent->position << ") <";
+    for (unsigned int i = 0 ; i < this->levels_ ; i++) {
+      msgBuffer << parent->label[i] << ",";
+    }
+    msgBuffer << ">";
+    msgBuffer << " related ? ";
+    XBT_DEBUG("%s", msgBuffer.str().c_str());
+    
   }
+  if (parent->level != child->level + 1) {
+    return false;
+  }
+  
+  for (unsigned int i = 0 ; i < this->levels_; i++) {
+    if (parent->label[i] != child->label[i] && i + 1 != parent->level) {
+      return false;
+    }
+  }
+  return true;
 }
 
-void AsClusterFatTree::getLevelPosition(const unsigned  int level, int *position, int *size) {
-  if (level > this->levels - 1) {
-    *position = -1;
-    *size =  -1;
+void AsClusterFatTree::generateSwitches() {
+  XBT_DEBUG("Generating switches.");
+  this->nodesByLevel_.resize(this->levels_ + 1, 0);
+  unsigned int nodesRequired = 0;
+
+  // Take care of the number of nodes by level
+  this->nodesByLevel_[0] = 1;
+  for (unsigned int i = 0 ; i < this->levels_ ; i++)
+    this->nodesByLevel_[0] *= this->lowerLevelNodesNumber_[i];
+     
+  if(this->nodesByLevel_[0] != this->nodes_.size()) {
+    surf_parse_error("The number of provided nodes does not fit with the wanted topology."
+                     " Please check your platform description (We need %d nodes, we got %zu)",
+                     this->nodesByLevel_[0], this->nodes_.size());
     return;
   }
-  int tempPosition = 0;
 
-  for (unsigned int i = 0 ; i < level ; i++) {
-    tempPosition += this->nodesByLevel[i];
+  
+  for (unsigned int i = 0 ; i < this->levels_ ; i++) {
+    int nodesInThisLevel = 1;
+      
+    for (unsigned int j = 0 ;  j <= i ; j++)
+      nodesInThisLevel *= this->upperLevelNodesNumber_[j];
+      
+    for (unsigned int j = i+1 ; j < this->levels_ ; j++)
+      nodesInThisLevel *= this->lowerLevelNodesNumber_[j];
+
+    this->nodesByLevel_[i+1] = nodesInThisLevel;
+    nodesRequired += nodesInThisLevel;
   }
-  *position = tempPosition;
-  *size = this->nodesByLevel[level];
-}
 
-void AsClusterFatTree::addNodes(std::vector<int> const& id) {
-  for (size_t  i = 0 ; i < id.size() ; i++) {
-    this->nodes.push_back(new FatTreeNode(id[i]));
+
+  // Create the switches
+  int k = 0;
+  for (unsigned int i = 0 ; i < this->levels_ ; i++) {
+    for (unsigned int j = 0 ; j < this->nodesByLevel_[i + 1] ; j++) {
+      FatTreeNode* newNode = new FatTreeNode(this->cluster_, --k, i + 1, j);
+      XBT_DEBUG("We create the switch %d(%d,%d)", newNode->id, newNode->level, newNode->position);
+      newNode->children.resize(this->lowerLevelNodesNumber_[i] *
+                               this->lowerLevelPortsNumber_[i]);
+      if (i != this->levels_ - 1) {
+        newNode->parents.resize(this->upperLevelNodesNumber_[i + 1] *
+                                this->lowerLevelPortsNumber_[i + 1]);
+      }
+      newNode->label.resize(this->levels_);
+      this->nodes_.push_back(newNode);
+    }
   }
 }
 
-void AsClusterFatTree::addLink(sg_platf_cluster_cbarg_t cluster, FatTreeNode *parent,
-                               FatTreeNode *child) {
-  using std::make_pair;
-  if (parent->children.size() == this->nodesByLevel[parent->level] ||
-      child->parents.size()   == this->nodesByLevel[child->level]) {
-    /* NB : This case should never happen, if this private function is not misused,
-     * so should we keep this test, keep it only for debug, throw an exception
-     * or get rid of it ? In all cases, anytime we get in there, code should be
-     * fixed
-     */
-    xbt_die("I've been asked to create a link that could not possibly exist");
-    return;
+void AsClusterFatTree::generateLabels() {
+  XBT_DEBUG("Generating labels.");
+  // TODO : check if nodesByLevel and nodes are filled
+  std::vector<int> maxLabel(this->levels_);
+  std::vector<int> currentLabel(this->levels_);
+  unsigned int k = 0;
+  for (unsigned int i = 0 ; i <= this->levels_ ; i++) {
+    currentLabel.assign(this->levels_, 0);
+    for (unsigned int j = 0 ; j < this->levels_ ; j++) {
+      maxLabel[j] = j + 1 > i ?
+        this->lowerLevelNodesNumber_[j] : this->upperLevelNodesNumber_[j];
+    }
+    
+    for (unsigned int j = 0 ; j < this->nodesByLevel_[i] ; j++) {
+
+      if(XBT_LOG_ISENABLED(surf_route_fat_tree, xbt_log_priority_debug )) {
+        std::stringstream msgBuffer;
+
+        msgBuffer << "Assigning label <";
+        for (unsigned int l = 0 ; l < this->levels_ ; l++) {
+          msgBuffer << currentLabel[l] << ",";
+        }
+        msgBuffer << "> to " << k << " (" << i << "," << j <<")";
+        
+        XBT_DEBUG("%s", msgBuffer.str().c_str());
+      }
+      this->nodes_[k]->label.assign(currentLabel.begin(), currentLabel.end());
+
+      bool remainder = true;
+      unsigned int pos = 0;
+      while (remainder && pos < this->levels_) {
+        ++currentLabel[pos];
+        if (currentLabel[pos] >= maxLabel[pos]) {
+          currentLabel[pos] = 0;
+          remainder = true;
+          ++pos;
+        }
+        else {
+          pos = 0;
+          remainder = false;
+        }
+      }
+      k++;
+    }
   }
+}
 
-  parent->children.push_back(child);
-  child->parents.push_back(parent);
 
-  FatTreeLink *newLink;
+int AsClusterFatTree::getLevelPosition(const unsigned  int level) {
+  xbt_assert(level <= this->levels_, "The impossible did happen. Yet again.");
+  int tempPosition = 0;
 
-  newLink = new FatTreeLink(cluster, parent, child, this->lowerLevelPortsNumber[parent->level]);
-   this->links.insert(make_pair(make_pair(parent->id, child->id), newLink));
+  for (unsigned int i = 0 ; i < level ; i++)
+    tempPosition += this->nodesByLevel_[i];
 
-  
+  return tempPosition;
+}
 
+void AsClusterFatTree::addProcessingNode(int id) {
+  using std::make_pair;
+  static int position = 0;
+  FatTreeNode* newNode;
+  newNode = new FatTreeNode(this->cluster_, id, 0, position++);
+  newNode->parents.resize(this->upperLevelNodesNumber_[0] *
+                          this->lowerLevelPortsNumber_[0]);
+  newNode->label.resize(this->levels_);
+  this->computeNodes_.insert(make_pair(id,newNode));
+  this->nodes_.push_back(newNode);
 }
 
-void AsClusterFatTree::parse_specific_arguments(sg_platf_cluster_cbarg_t 
-                                                cluster) {
-  std::vector<string> parameters;
-  std::vector<string> tmp;
+void AsClusterFatTree::addLink(FatTreeNode *parent, unsigned int parentPort,
+                               FatTreeNode *child, unsigned int childPort) {
+  FatTreeLink *newLink;
+  newLink = new FatTreeLink(this->cluster_, child, parent);
+  XBT_DEBUG("Creating a link between the parent (%d,%d,%u) and the child (%d,%d,%u)",
+      parent->level, parent->position, parentPort, child->level, child->position, childPort);
+  parent->children[parentPort] = newLink;
+  child->parents[childPort] = newLink;
+
+  this->links_.push_back(newLink);
+}
+
+void AsClusterFatTree::parse_specific_arguments(sg_platf_cluster_cbarg_t cluster) {
+  std::vector<std::string> parameters;
+  std::vector<std::string> tmp;
   boost::split(parameters, cluster->topo_parameters, boost::is_any_of(";"));
- 
 
   // TODO : we have to check for zeros and negative numbers, or it might crash
   if (parameters.size() != 4){
-    surf_parse_error("Fat trees are defined by the levels number and 3 vectors" 
-                     ", see the documentation for more informations");
-    // Well, there's no doc, yet
+    surf_parse_error("Fat trees are defined by the levels number and 3 vectors, see the documentation for more informations");
   }
 
   // The first parts of topo_parameters should be the levels number
-  this->levels = std::atoi(tmp[0].c_str()); // stoi() only in C++11...
+  this->levels_ = xbt_str_parse_int(parameters[0].c_str(), "First parameter is not the amount of levels: %s");
   
   // Then, a l-sized vector standing for the childs number by level
   boost::split(tmp, parameters[1], boost::is_any_of(","));
-  if(tmp.size() != this->levels) {
+  if(tmp.size() != this->levels_) {
     surf_parse_error("Fat trees are defined by the levels number and 3 vectors" 
                      ", see the documentation for more informations"); 
   }
   for(size_t i = 0 ; i < tmp.size() ; i++){
-    this->lowerLevelNodesNumber.push_back(std::atoi(tmp[i].c_str())); 
+    this->lowerLevelNodesNumber_.push_back(xbt_str_parse_int(tmp[i].c_str(), "Invalid lower level node number: %s"));
   }
   
   // Then, a l-sized vector standing for the parents number by level
   boost::split(tmp, parameters[2], boost::is_any_of(","));
-  if(tmp.size() != this->levels) {
+  if(tmp.size() != this->levels_) {
     surf_parse_error("Fat trees are defined by the levels number and 3 vectors" 
                      ", see the documentation for more informations"); 
   }
   for(size_t i = 0 ; i < tmp.size() ; i++){
-    this->upperLevelNodesNumber.push_back(std::atoi(tmp[i].c_str())); 
+    this->upperLevelNodesNumber_.push_back(xbt_str_parse_int(tmp[i].c_str(), "Invalid upper level node number: %s"));
   }
   
   // Finally, a l-sized vector standing for the ports number with the lower level
   boost::split(tmp, parameters[3], boost::is_any_of(","));
-  if(tmp.size() != this->levels) {
+  if(tmp.size() != this->levels_) {
     surf_parse_error("Fat trees are defined by the levels number and 3 vectors" 
                      ", see the documentation for more informations"); 
     
   }
   for(size_t i = 0 ; i < tmp.size() ; i++){
-    this->lowerLevelPortsNumber.push_back(std::atoi(tmp[i].c_str())); 
+    this->lowerLevelPortsNumber_.push_back(xbt_str_parse_int(tmp[i].c_str(), "Invalid lower level node number: %s"));
   }
+  this->cluster_ = cluster;
 }
 
 
-void AsClusterFatTree::generateDotFile(const string& filename) const {
-  ofstream file;
-  /* Maybe should we get directly a char*, as open takes strings only beginning
-   * with C++11...
-   */
-  file.open(filename.c_str(), ios::out | ios::trunc); 
-  
-  if(file.is_open()) {
-    // That could also be greatly clarified with C++11
-    std::map<std::pair<int,int>,FatTreeLink*>::const_iterator iter;
-    file << "graph AsClusterFatTree {\n";
-    for (iter = this->links.begin() ; iter != this->links.end() ; iter++ ) {
-      for (unsigned int j = 0 ; j < iter->second->ports ; j++) {
-        file << iter->second->source->id
-             << " -- "
-             << iter->second->destination->id
-             << ";\n";
-      }
-    }
-    file << "}";
-    file.close();
+void AsClusterFatTree::generateDotFile(const std::string& filename) const {
+  std::ofstream file;
+  file.open(filename, std::ios::out | std::ios::trunc);
+  xbt_assert(file.is_open(), "Unable to open file %s", filename.c_str());
+
+  file << "graph AsClusterFatTree {\n";
+  for (unsigned int i = 0 ; i < this->nodes_.size() ; i++) {
+    file << this->nodes_[i]->id;
+    if(this->nodes_[i]->id < 0)
+      file << " [shape=circle];\n";
+    else
+      file << " [shape=hexagon];\n";
   }
-  else {
-    std::cerr << "Unable to open file " << filename << std::endl;
-    return;
+
+  for (unsigned int i = 0 ; i < this->links_.size() ; i++ ) {
+    file << this->links_[i]->downNode->id
+        << " -- "
+        << this->links_[i]->upNode->id
+        << ";\n";
   }
+  file << "}";
+  file.close();
 }
 
-FatTreeNode::FatTreeNode(int id, int level, int position) : id(id),
-                                                            level(level),
-                                                            position(position){}
+FatTreeNode::FatTreeNode(sg_platf_cluster_cbarg_t cluster, int id, int level,
+                         int position) : id(id), level(level),
+                                         position(position) {
+  s_sg_platf_link_cbarg_t linkTemplate = SG_PLATF_LINK_INITIALIZER;
+  if(cluster->limiter_link) {
+    memset(&linkTemplate, 0, sizeof(linkTemplate));
+    linkTemplate.bandwidth = cluster->limiter_link;
+    linkTemplate.latency = 0;
+    linkTemplate.initiallyOn = 1;
+    linkTemplate.policy = SURF_LINK_SHARED;
+    linkTemplate.id = bprintf("limiter_%d", id);
+    sg_platf_new_link(&linkTemplate);
+    this->limiterLink = Link::byName(linkTemplate.id);
+    free((void*)linkTemplate.id);
+  }
+  if(cluster->loopback_bw || cluster->loopback_lat) {
+    memset(&linkTemplate, 0, sizeof(linkTemplate));
+    linkTemplate.bandwidth = cluster->loopback_bw;
+    linkTemplate.latency = cluster->loopback_lat;
+    linkTemplate.initiallyOn = 1;
+    linkTemplate.policy = SURF_LINK_FATPIPE;
+    linkTemplate.id = bprintf("loopback_%d", id);
+    sg_platf_new_link(&linkTemplate);
+    this->loopback = Link::byName(linkTemplate.id);
+    free((void*)linkTemplate.id);
+  }  
+}
 
-FatTreeLink::FatTreeLink(sg_platf_cluster_cbarg_t cluster, FatTreeNode *source,
-                         FatTreeNode *destination,
-                         unsigned int ports) : ports(ports), source(source),
-                                               destination(destination) {
-  s_sg_platf_link_cbarg_t linkTemplate;
+FatTreeLink::FatTreeLink(sg_platf_cluster_cbarg_t cluster,
+                         FatTreeNode *downNode,
+                         FatTreeNode *upNode) : upNode(upNode),
+                                                downNode(downNode) {
+  static int uniqueId = 0;
+  s_sg_platf_link_cbarg_t linkTemplate = SG_PLATF_LINK_INITIALIZER;
+  memset(&linkTemplate, 0, sizeof(linkTemplate));
   linkTemplate.bandwidth = cluster->bw;
   linkTemplate.latency = cluster->lat;
-  linkTemplate.state = SURF_RESOURCE_ON;
-  linkTemplate.policy = cluster->sharing_policy; // Maybe should we do sthg with that ?
-
-  for(unsigned int i = 0 ; i < ports ; i++) {
-    NetworkLink* link;
-    linkTemplate.id = bprintf("link_from_%d_to_%d_%d_UP", source->id, destination->id, i);
-    sg_platf_new_link(&linkTemplate);
-    link = (NetworkLink*) xbt_lib_get_or_null(link_lib, linkTemplate.id, SURF_LINK_LEVEL);
-    this->linksUp.push_back(link); // check link?
-    linkTemplate.id = bprintf("link_from_%d_to_%d_%d_DOWN", source->id, destination->id, i);
-    sg_platf_new_link(&linkTemplate);
-    link = (NetworkLink*) xbt_lib_get_or_null(link_lib, linkTemplate.id, SURF_LINK_LEVEL);
-    this->linksDown.push_back(link); // check link ?
+  linkTemplate.initiallyOn = 1;
+  linkTemplate.policy = cluster->sharing_policy; // sthg to do with that ?
+  linkTemplate.id = bprintf("link_from_%d_to_%d_%d", downNode->id, upNode->id,
+                            uniqueId);
+  sg_platf_new_link(&linkTemplate);
+  Link* link;
+  std::string tmpID;
+  if (cluster->sharing_policy == SURF_LINK_FULLDUPLEX) {
+    tmpID = std::string(linkTemplate.id) + "_UP";
+    link =  Link::byName(tmpID.c_str());
+    this->upLink = link; // check link?
+    tmpID = std::string(linkTemplate.id) + "_DOWN";
+    link = Link::byName(tmpID.c_str());
+    this->downLink = link; // check link ?
+  }
+  else {
+    link = Link::byName(linkTemplate.id);
+    this->upLink = link;
+    this->downLink = link;
   }
+  uniqueId++;
+  free((void*)linkTemplate.id);
+}
+
+}
 }