From e7f2da517adbc9ba4ed1b33de102126260a0d587 Mon Sep 17 00:00:00 2001
From: Brad Beckmann <Brad.Beckmann@amd.com>
Date: Fri, 20 Aug 2010 11:46:14 -0700
Subject: ruby: Stall and wait input messages instead of recycling

This patch allows messages to be stalled in their input buffers and wait
until a corresponding address changes state.  In order to make this work,
all in_ports must be ranked in order of dependence and those in_ports that
may unblock an address, must wake up the stalled messages.  Alot of this
complexity is handled in slicc and the specification files simply
annotate the in_ports.

--HG--
rename : src/mem/slicc/ast/CheckAllocateStatementAST.py => src/mem/slicc/ast/StallAndWaitStatementAST.py
rename : src/mem/slicc/ast/CheckAllocateStatementAST.py => src/mem/slicc/ast/WakeUpDependentsStatementAST.py
---
 src/mem/ruby/buffers/MessageBuffer.cc | 43 +++++++++++++++++++++++++++++++++++
 src/mem/ruby/buffers/MessageBuffer.hh |  9 ++++++++
 2 files changed, 52 insertions(+)

(limited to 'src/mem/ruby')

diff --git a/src/mem/ruby/buffers/MessageBuffer.cc b/src/mem/ruby/buffers/MessageBuffer.cc
index 9cd1dd47b..7d28cef22 100644
--- a/src/mem/ruby/buffers/MessageBuffer.cc
+++ b/src/mem/ruby/buffers/MessageBuffer.cc
@@ -334,6 +334,49 @@ MessageBuffer::recycle()
         g_eventQueue_ptr->getTime() + m_recycle_latency);
 }
 
+void
+MessageBuffer::reanalyzeMessages(const Address& addr)
+{
+    DEBUG_MSG(QUEUE_COMP, MedPrio, "reanalyzeMessages " + m_name);
+    assert(m_stall_msg_map.count(addr) > 0);
+
+    //
+    // Put all stalled messages associated with this address back on the
+    // prio heap
+    //
+    while(!m_stall_msg_map[addr].empty()) {
+        m_msg_counter++;
+        MessageBufferNode msgNode(g_eventQueue_ptr->getTime() + 1, 
+                                  m_msg_counter, 
+                                  m_stall_msg_map[addr].front());
+
+        m_prio_heap.push_back(msgNode);
+        push_heap(m_prio_heap.begin(), m_prio_heap.end(),
+            greater<MessageBufferNode>());
+
+        g_eventQueue_ptr->scheduleEventAbsolute(m_consumer_ptr, msgNode.m_time);
+        m_stall_msg_map[addr].pop_front();
+    }
+}
+
+void
+MessageBuffer::stallMessage(const Address& addr)
+{
+    DEBUG_MSG(QUEUE_COMP, MedPrio, "stalling " + m_name);
+    assert(isReady());
+    assert(addr.getOffset() == 0);
+    MsgPtr message = m_prio_heap.front().m_msgptr;
+
+    pop();
+
+    //
+    // Note: no event is scheduled to analyze the map at a later time.
+    // Instead the controller is responsible to call reanalyzeMessages when
+    // these addresses change state.
+    //
+    (m_stall_msg_map[addr]).push_back(message);
+}
+
 int
 MessageBuffer::setAndReturnDelayCycles(MsgPtr msg_ptr)
 {
diff --git a/src/mem/ruby/buffers/MessageBuffer.hh b/src/mem/ruby/buffers/MessageBuffer.hh
index e4bee5cf6..e09abeb7d 100644
--- a/src/mem/ruby/buffers/MessageBuffer.hh
+++ b/src/mem/ruby/buffers/MessageBuffer.hh
@@ -45,6 +45,7 @@
 #include "mem/ruby/common/Global.hh"
 #include "mem/ruby/eventqueue/RubyEventQueue.hh"
 #include "mem/ruby/slicc_interface/Message.hh"
+#include "mem/ruby/common/Address.hh"
 
 class MessageBuffer
 {
@@ -58,6 +59,9 @@ class MessageBuffer
         m_recycle_latency = recycle_latency;
     }
 
+    void reanalyzeMessages(const Address& addr);
+    void stallMessage(const Address& addr);
+
     // TRUE if head of queue timestamp <= SystemTime
     bool
     isReady() const
@@ -150,6 +154,11 @@ class MessageBuffer
     // Data Members (m_ prefix)
     Consumer* m_consumer_ptr;  // Consumer to signal a wakeup(), can be NULL
     std::vector<MessageBufferNode> m_prio_heap;
+    
+    typedef m5::hash_map< Address, std::list<MsgPtr> > StallMsgMapType;
+    typedef std::vector<MsgPtr>::iterator MsgListIter;
+
+    StallMsgMapType m_stall_msg_map;
     std::string m_name;
 
     int m_max_size;
-- 
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