ruby: improved support for functional accesses

This patch adds support to different entities in the ruby memory system
for more reliable functional read/write accesses. Only the simple network
has been augmented as of now. Later on Garnet will also support functional
accesses.
The patch adds functional access code to all the different types of messages
that protocols can send around. These messages are functionally accessed
by going through the buffers maintained by the network entities.
The patch also rectifies some of the bugs found in coherence protocols while
testing the patch.

With this patch applied, functional writes always succeed. But functional
reads can still fail.

3 files changed, 79 insertions, 8 deletions

diff --git a/src/mem/ruby/buffers/MessageBuffer.cc b/src/mem/ruby/buffers/MessageBuffer.cc
index f0d372a52..f960cc033 100644
--- a/src/mem/ruby/buffers/MessageBuffer.cc
+++ b/src/mem/ruby/buffers/MessageBuffer.cc
@@ -435,3 +435,69 @@ MessageBuffer::printStats(ostream& out)
     out << "MessageBuffer: " << m_name << " stats - msgs:" << m_msg_counter
         << " full:" << m_not_avail_count << endl;
 }
+
+bool
+MessageBuffer::isReady() const
+{
+    return ((m_prio_heap.size() > 0) &&
+            (m_prio_heap.front().m_time <= g_system_ptr->getTime()));
+}
+
+bool
+MessageBuffer::functionalRead(Packet *pkt)
+{
+    // Check the priority heap and read any messages that may
+    // correspond to the address in the packet.
+    for (unsigned int i = 0; i < m_prio_heap.size(); ++i) {
+        Message *msg = m_prio_heap[i].m_msgptr.get();
+        if (msg->functionalRead(pkt)) return true;
+    }
+
+    // Read the messages in the stall queue that correspond
+    // to the address in the packet.
+    for (StallMsgMapType::iterator map_iter = m_stall_msg_map.begin();
+         map_iter != m_stall_msg_map.end();
+         ++map_iter) {
+
+        for (std::list<MsgPtr>::iterator it = (map_iter->second).begin();
+            it != (map_iter->second).end(); ++it) {
+
+            Message *msg = (*it).get();
+            if (msg->functionalRead(pkt)) return true;
+        }
+    }
+    return false;
+}
+
+uint32_t
+MessageBuffer::functionalWrite(Packet *pkt)
+{
+    uint32_t num_functional_writes = 0;
+
+    // Check the priority heap and write any messages that may
+    // correspond to the address in the packet.
+    for (unsigned int i = 0; i < m_prio_heap.size(); ++i) {
+        Message *msg = m_prio_heap[i].m_msgptr.get();
+        if (msg->functionalWrite(pkt)) {
+            num_functional_writes++;
+        }
+    }
+
+    // Check the stall queue and write any messages that may
+    // correspond to the address in the packet.
+    for (StallMsgMapType::iterator map_iter = m_stall_msg_map.begin();
+         map_iter != m_stall_msg_map.end();
+         ++map_iter) {
+
+        for (std::list<MsgPtr>::iterator it = (map_iter->second).begin();
+            it != (map_iter->second).end(); ++it) {
+
+            Message *msg = (*it).get();
+            if (msg->functionalWrite(pkt)) {
+                num_functional_writes++;
+            }
+        }
+    }
+
+    return num_functional_writes;
+}
diff --git a/src/mem/ruby/buffers/MessageBuffer.hh b/src/mem/ruby/buffers/MessageBuffer.hh
index cf7e77c2d..c4fd7165d 100644
--- a/src/mem/ruby/buffers/MessageBuffer.hh
+++ b/src/mem/ruby/buffers/MessageBuffer.hh
@@ -41,10 +41,10 @@
 #include <string>
 #include <vector>
 
+#include "mem/packet.hh"
 #include "mem/ruby/buffers/MessageBufferNode.hh"
 #include "mem/ruby/common/Address.hh"
 #include "mem/ruby/common/Consumer.hh"
-#include "mem/ruby/common/Global.hh"
 #include "mem/ruby/slicc_interface/Message.hh"
 
 class MessageBuffer
@@ -65,12 +65,7 @@ class MessageBuffer
     void stallMessage(const Address& addr);
 
     // TRUE if head of queue timestamp <= SystemTime
-    bool
-    isReady() const
-    {
-        return ((m_prio_heap.size() > 0) &&
-                (m_prio_heap.front().m_time <= g_system_ptr->getTime()));
-    }
+    bool isReady() const;
 
     void
     delayHead()
@@ -145,6 +140,17 @@ class MessageBuffer
     void setIncomingLink(int link_id) { m_input_link_id = link_id; }
     void setVnet(int net) { m_vnet_id = net; }
 
+    // Function for figuring out if any of the messages in the buffer can
+    // satisfy the read request for the address in the packet.
+    // Return value, if true, indicates that the request was fulfilled.
+    bool functionalRead(Packet *pkt);
+
+    // Function for figuring out if any of the messages in the buffer need
+    // to be updated with the data from the packet.
+    // Return value indicates the number of messages that were updated.
+    // This required for debugging the code.
+    uint32_t functionalWrite(Packet *pkt);
+
   private:
     //added by SS
     int m_recycle_latency;
diff --git a/src/mem/ruby/buffers/MessageBufferNode.hh b/src/mem/ruby/buffers/MessageBufferNode.hh
index 70afa9831..5e7a52e12 100644
--- a/src/mem/ruby/buffers/MessageBufferNode.hh
+++ b/src/mem/ruby/buffers/MessageBufferNode.hh
@@ -31,7 +31,6 @@
 
 #include <iostream>
 
-#include "mem/ruby/common/Global.hh"
 #include "mem/ruby/slicc_interface/Message.hh"
 
 class MessageBufferNode