ruby: message buffer, timer table: significant changes

This patch changes MessageBuffer and TimerTable, two structures used for
buffering messages by components in ruby.  These structures would no longer
maintain pointers to clock objects.  Functions in these structures have been
changed to take as input current time in Tick.  Similarly, these structures
will not operate on Cycle valued latencies for different operations.  The
corresponding functions would need to be provided with these latencies by
components invoking the relevant functions.  These latencies should also be
in Ticks.

I felt the need for these changes while trying to speed up ruby.  The ultimate
aim is to eliminate Consumer class and replace it with an EventManager object in
the MessageBuffer and TimerTable classes.  This object would be used for
scheduling events.  The event itself would contain information on the object and
function to be invoked.

In hindsight, it seems I should have done this while I was moving away from use
of a single global clock in the memory system.  That change led to introduction
of clock objects that replaced the global clock object.  It never crossed my
mind that having clock object pointers is not a good design.  And now I really
don't like the fact that we have separate consumer, receiver and sender
pointers in message buffers.

3 files changed, 12 insertions, 30 deletions

diff --git a/src/mem/ruby/structures/TBETable.hh b/src/mem/ruby/structures/TBETable.hh
index cbc51dae5..4a24a5b13 100644
--- a/src/mem/ruby/structures/TBETable.hh
+++ b/src/mem/ruby/structures/TBETable.hh
@@ -47,12 +47,12 @@ class TBETable
     void allocate(Addr address);
     void deallocate(Addr address);
     bool
-    areNSlotsAvailable(int n) const
+    areNSlotsAvailable(int n, Tick current_time) const
     {
         return (m_number_of_TBEs - m_map.size()) >= n;
     }
 
-    ENTRY* lookup(Addr address);
+    ENTRY *lookup(Addr address);
 
     // Print cache contents
     void print(std::ostream& out) const;
diff --git a/src/mem/ruby/structures/TimerTable.cc b/src/mem/ruby/structures/TimerTable.cc
index 17dac6fc0..4809c8a47 100644
--- a/src/mem/ruby/structures/TimerTable.cc
+++ b/src/mem/ruby/structures/TimerTable.cc
@@ -34,14 +34,12 @@ TimerTable::TimerTable()
     : m_next_time(0)
 {
     m_consumer_ptr  = NULL;
-    m_clockobj_ptr = NULL;
-
     m_next_valid = false;
     m_next_address = 0;
 }
 
 bool
-TimerTable::isReady() const
+TimerTable::isReady(Tick curTime) const
 {
     if (m_map.empty())
         return false;
@@ -50,14 +48,12 @@ TimerTable::isReady() const
         updateNext();
     }
     assert(m_next_valid);
-    return (m_clockobj_ptr->curCycle() >= m_next_time);
+    return (curTime >= m_next_time);
 }
 
 Addr
-TimerTable::readyAddress() const
+TimerTable::nextAddress() const
 {
-    assert(isReady());
-
     if (!m_next_valid) {
         updateNext();
     }
@@ -66,17 +62,14 @@ TimerTable::readyAddress() const
 }
 
 void
-TimerTable::set(Addr address, Cycles relative_latency)
+TimerTable::set(Addr address, Tick ready_time)
 {
     assert(address == makeLineAddress(address));
-    assert(relative_latency > 0);
     assert(!m_map.count(address));
 
-    Cycles ready_time = m_clockobj_ptr->curCycle() + relative_latency;
     m_map[address] = ready_time;
     assert(m_consumer_ptr != NULL);
-    m_consumer_ptr->
-        scheduleEventAbsolute(m_clockobj_ptr->clockPeriod() * ready_time);
+    m_consumer_ptr->scheduleEventAbsolute(ready_time);
     m_next_valid = false;
 
     // Don't always recalculate the next ready address
diff --git a/src/mem/ruby/structures/TimerTable.hh b/src/mem/ruby/structures/TimerTable.hh
index 606201eb4..9efe7ca04 100644
--- a/src/mem/ruby/structures/TimerTable.hh
+++ b/src/mem/ruby/structures/TimerTable.hh
@@ -49,25 +49,16 @@ class TimerTable
         m_consumer_ptr = consumer_ptr;
     }
 
-    void setClockObj(ClockedObject* obj)
-    {
-        assert(m_clockobj_ptr == NULL);
-        m_clockobj_ptr = obj;
-    }
-
     void
     setDescription(const std::string& name)
     {
         m_name = name;
     }
 
-    bool isReady() const;
-    Addr readyAddress() const;
+    bool isReady(Tick curTime) const;
+    Addr nextAddress() const;
     bool isSet(Addr address) const { return !!m_map.count(address); }
-    void set(Addr address, Cycles relative_latency);
-    void set(Addr address, uint64_t relative_latency)
-    { set(address, Cycles(relative_latency)); }
-
+    void set(Addr address, Tick ready_time);
     void unset(Addr address);
     void print(std::ostream& out) const;
 
@@ -82,14 +73,12 @@ class TimerTable
 
     // use a std::map for the address map as this container is sorted
     // and ensures a well-defined iteration order
-    typedef std::map<Addr, Cycles> AddressMap;
+    typedef std::map<Addr, Tick> AddressMap;
     AddressMap m_map;
     mutable bool m_next_valid;
-    mutable Cycles m_next_time; // Only valid if m_next_valid is true
+    mutable Tick m_next_time; // Only valid if m_next_valid is true
     mutable Addr m_next_address;  // Only valid if m_next_valid is true
 
-    //! Object used for querying time.
-    ClockedObject* m_clockobj_ptr;
     //! Consumer to signal a wakeup()
     Consumer* m_consumer_ptr;