1 files changed, 66 insertions, 0 deletions
diff --git a/src/mem/ruby/network/simple/HierarchicalSwitchTopology.cc b/src/mem/ruby/network/simple/HierarchicalSwitchTopology.cc
new file mode 100644
index 000000000..c0190e789
--- /dev/null
+++ b/src/mem/ruby/network/simple/HierarchicalSwitchTopology.cc
@@ -0,0 +1,66 @@
+
+#include "mem/ruby/network/simple/HierarchicalSwitchTopology.hh"
+
+// hierarchical switch topology
+void Topology::construct(int fan_out_degree)
+{
+  // Make a row of switches with only one input.  This extra row makes
+  // sure the links out of the nodes have latency and limited
+  // bandwidth.
+
+  // number of inter-chip switches, i.e. the last row of switches
+  Vector<SwitchID> last_level;
+  for (int i=0; i<m_nodes; i++) {
+    SwitchID new_switch = newSwitchID();  // internal switch id #
+    addLink(i, new_switch, m_network_ptr->getLinkLatency());
+    last_level.insertAtBottom(new_switch);
+  }
+
+  // Create Hierarchical Switches
+
+  // start from the bottom level and work up to root
+  Vector<SwitchID> next_level;
+  while(last_level.size() > 1) {
+    for (int i=0; i<last_level.size(); i++) {
+      if ((i % fan_out_degree) == 0) {
+        next_level.insertAtBottom(newSwitchID());
+      }
+      // Add this link to the last switch we created
+      addLink(last_level[i], next_level[next_level.size()-1], m_network_ptr->getLinkLatency());
+    }
+
+    // Make the current level the last level to get ready for next
+    // iteration
+    last_level = next_level;
+    next_level.clear();
+  }
+
+  SwitchID root_switch = last_level[0];
+
+  Vector<SwitchID> out_level;
+  for (int i=0; i<m_nodes; i++) {
+    out_level.insertAtBottom(m_nodes+i);
+  }
+
+  // Build the down network from the endpoints to the root
+  while(out_level.size() != 1) {
+
+    // A level of switches
+    for (int i=0; i<out_level.size(); i++) {
+      if ((i % fan_out_degree) == 0) {
+        if (out_level.size() > fan_out_degree) {
+          next_level.insertAtBottom(newSwitchID());
+        } else {
+          next_level.insertAtBottom(root_switch);
+        }
+      }
+      // Add this link to the last switch we created
+      addLink(next_level[next_level.size()-1], out_level[i], m_network_ptr->getLinkLatency());
+    }
+
+    // Make the current level the last level to get ready for next
+    // iteration
+    out_level = next_level;
+    next_level.clear();
+  }
+}