ruby: network: revert some of the changes from ad9c042dce54

The changeset ad9c042dce54 made changes to the structures under the network
directory to use a map of buffers instead of vector of buffers.
The reasoning was that not all vnets that are created are used and we
needlessly allocate more buffers than required and then iterate over them
while processing network messages.  But the move to map resulted in a slow
down which was pointed out by Andreas Hansson.  This patch moves things
back to using vector of message buffers.

1 files changed, 18 insertions, 21 deletions

diff --git a/src/mem/ruby/network/simple/Throttle.cc b/src/mem/ruby/network/simple/Throttle.cc
index 91bad217b..2da810edb 100644
--- a/src/mem/ruby/network/simple/Throttle.cc
+++ b/src/mem/ruby/network/simple/Throttle.cc
@@ -69,6 +69,8 @@ Throttle::init(NodeID node, Cycles link_latency,
                int link_bandwidth_multiplier, int endpoint_bandwidth)
 {
     m_node = node;
+    m_vnets = 0;
+
     assert(link_bandwidth_multiplier > 0);
     m_link_bandwidth_multiplier = link_bandwidth_multiplier;
 
@@ -80,23 +82,19 @@ Throttle::init(NodeID node, Cycles link_latency,
 }
 
 void
-Throttle::addLinks(const map<int, MessageBuffer*>& in_vec,
-                   const map<int, MessageBuffer*>& out_vec)
+Throttle::addLinks(const vector<MessageBuffer*>& in_vec,
+                   const vector<MessageBuffer*>& out_vec)
 {
     assert(in_vec.size() == out_vec.size());
 
-    for (auto& it : in_vec) {
-        int vnet = it.first;
-
-        auto jt = out_vec.find(vnet);
-        assert(jt != out_vec.end());
+    for (int vnet = 0; vnet < in_vec.size(); ++vnet) {
+        MessageBuffer *in_ptr = in_vec[vnet];
+        MessageBuffer *out_ptr = out_vec[vnet];
 
-        MessageBuffer *in_ptr = it.second;
-        MessageBuffer *out_ptr = (*jt).second;
-
-        m_in[vnet] = in_ptr;
-        m_out[vnet] = out_ptr;
-        m_units_remaining[vnet] = 0;
+        m_vnets++;
+        m_units_remaining.push_back(0);
+        m_in.push_back(in_ptr);
+        m_out.push_back(out_ptr);
 
         // Set consumer and description
         in_ptr->setConsumer(this);
@@ -110,8 +108,9 @@ void
 Throttle::operateVnet(int vnet, int &bw_remaining, bool &schedule_wakeup,
                       MessageBuffer *in, MessageBuffer *out)
 {
-    assert(out != NULL);
-    assert(in != NULL);
+    if (out == nullptr || in == nullptr) {
+        return;
+    }
     assert(m_units_remaining[vnet] >= 0);
 
     while (bw_remaining > 0 && (in->isReady() || m_units_remaining[vnet] > 0) &&
@@ -178,16 +177,14 @@ Throttle::wakeup()
     }
 
     if (iteration_direction) {
-        for (auto& it : m_in) {
-            int vnet = it.first;
+        for (int vnet = 0; vnet < m_vnets; ++vnet) {
             operateVnet(vnet, bw_remaining, schedule_wakeup,
-                        it.second, m_out[vnet]);
+                        m_in[vnet], m_out[vnet]);
         }
     } else {
-        for (auto it = m_in.rbegin(); it != m_in.rend(); ++it) {
-            int vnet = (*it).first;
+        for (int vnet = m_vnets-1; vnet >= 0; --vnet) {
             operateVnet(vnet, bw_remaining, schedule_wakeup,
-                        (*it).second, m_out[vnet]);
+                        m_in[vnet], m_out[vnet]);
         }
     }