sim: simulate with multiple threads and event queues

This patch adds support for simulating with multiple threads, each of
which operates on an event queue.  Each sim object specifies which eventq
is would like to be on.  A custom barrier implementation is being added
using which eventqs synchronize.

The patch was tested in two different configurations:
1. ruby_network_test.py: in this simulation L1 cache controllers receive
   requests from the cpu. The requests are replied to immediately without
   any communication taking place with any other level.
2. twosys-tsunami-simple-atomic: this configuration simulates a client-server
   system which are connected by an ethernet link.

We still lack the ability to communicate using message buffers or ports. But
other things like simulation start and end, synchronizing after every quantum
are working.

Committed by: Nilay Vaish

src/python/m5/SimObject.py

@@ -11,7 +11,8 @@
 # modified or unmodified, in source code or in binary form.
 #
 # Copyright (c) 2004-2006 The Regents of The University of Michigan
-# Copyright (c) 2010 Advanced Micro Devices, Inc.
+# Copyright (c) 2010-20013 Advanced Micro Devices, Inc.
+# Copyright (c) 2013 Mark D. Hill and David A. Wood
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -528,8 +529,6 @@ struct PyObject;
 #endif
 
 #include <string>
-
-class EventQueue;
 ''')
         for param in params:
             param.cxx_predecls(code)
@@ -558,16 +557,11 @@ class EventQueue;
         code.indent()
         if cls == SimObject:
             code('''
-    SimObjectParams()
-    {
-        extern EventQueue mainEventQueue;
-        eventq = &mainEventQueue;
-    }
+    SimObjectParams() {}
     virtual ~SimObjectParams() {}
 
     std::string name;
     PyObject *pyobj;
-    EventQueue *eventq;
             ''')
         for param in params:
             param.cxx_decl(code)
@@ -582,6 +576,14 @@ class EventQueue;
         return code
 
 
+# This *temporary* definition is required to support calls from the
+# SimObject class definition to the MetaSimObject methods (in
+# particular _set_param, which gets called for parameters with default
+# values defined on the SimObject class itself).  It will get
+# overridden by the permanent definition (which requires that
+# SimObject be defined) lower in this file.
+def isSimObjectOrVector(value):
+    return False
 
 # The SimObject class is the root of the special hierarchy.  Most of
 # the code in this class deals with the configuration hierarchy itself
@@ -592,9 +594,10 @@ class SimObject(object):
     __metaclass__ = MetaSimObject
     type = 'SimObject'
     abstract = True
-    cxx_header = "sim/sim_object.hh"
 
+    cxx_header = "sim/sim_object.hh"
     cxx_bases = [ "Drainable", "Serializable" ]
+    eventq_index = Param.UInt32(Parent.eventq_index, "Event Queue Index")
 
     @classmethod
     def export_method_swig_predecls(cls, code):

src/python/m5/event.py

@@ -1,4 +1,6 @@
 # Copyright (c) 2006 The Regents of The University of Michigan
+# Copyright (c) 2013 Advanced Micro Devices, Inc.
+# Copyright (c) 2013 Mark D. Hill and David A. Wood
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -29,9 +31,9 @@
 import m5
 import internal.event
 
-from internal.event import PythonEvent, SimLoopExitEvent as SimExit
+from internal.event import PythonEvent, GlobalSimLoopExitEvent as SimExit
 
-mainq = internal.event.cvar.mainEventQueue
+mainq = None
 
 def create(obj, priority=None):
     if priority is None:
@@ -58,4 +60,10 @@ class ProgressEvent(Event):
         print "Progress! Time now %fs" % (m5.curTick()/1e12)
         self.eventq.schedule(self, m5.curTick() + self.period)
 
+def getEventQueue(index):
+    return internal.event.getEventQueue(index)
+
+def setEventQueue(eventq):
+    internal.event.curEventQueue(eventq)
+
 __all__ = [ 'create', 'Event', 'ProgressEvent', 'SimExit', 'mainq' ]

src/python/m5/main.py

@@ -190,6 +190,10 @@ def main(*args):
 
         fatal("Tracing is not enabled.  Compile with TRACING_ON")
 
+    # Set the main event queue for the main thread.
+    event.mainq = event.getEventQueue(0)
+    event.setEventQueue(event.mainq)
+
     if not os.path.isdir(options.outdir):
         os.makedirs(options.outdir)
 

src/python/m5/simulate.py

@@ -147,6 +147,13 @@ def simulate(*args, **kwargs):
         for obj in root.descendants(): obj.startup()
         need_startup = False
 
+        # Python exit handlers happen in reverse order.
+        # We want to dump stats last.
+        atexit.register(stats.dump)
+
+        # register our C++ exit callback function with Python
+        atexit.register(internal.core.doExitCleanup)
+
     for root in need_resume:
         resume(root)
     need_resume = []
@@ -157,12 +164,6 @@ def simulate(*args, **kwargs):
 def curTick():
     return internal.core.curTick()
 
-# Python exit handlers happen in reverse order.  We want to dump stats last.
-atexit.register(stats.dump)
-
-# register our C++ exit callback function with Python
-atexit.register(internal.core.doExitCleanup)
-
 # Drain the system in preparation of a checkpoint or memory mode
 # switch.
 def drain(root):

src/python/swig/event.i

@@ -1,5 +1,7 @@
 /*
  * Copyright (c) 2006 The Regents of The University of Michigan
+ * Copyright (c) 2013 Advanced Micro Devices, Inc.
+ * Copyright (c) 2013 Mark D. Hill and David A. Wood
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -82,12 +84,13 @@
 %include "python/swig/pyevent.hh"
 
 // minimal definition of SimExitEvent interface to wrap
-class SimLoopExitEvent : public Event
+class GlobalSimLoopExitEvent
 {
   public:
     std::string getCause();
     int getCode();
-    SimLoopExitEvent(const std::string &_cause, int c, Tick _repeat = 0);
+    GlobalSimLoopExitEvent(Tick when, const std::string &_cause, int c,
+                           Tick _repeat = 0);
 };
 
 %exception simulate {
@@ -96,5 +99,8 @@ class SimLoopExitEvent : public Event
         return NULL;
     }
 }
-SimLoopExitEvent *simulate(Tick num_cycles = MaxTick);
+
+GlobalSimLoopExitEvent *simulate(Tick num_cycles = MaxTick);
 void exitSimLoop(const std::string &message, int exit_code);
+void curEventQueue( EventQueue *);
+EventQueue *getEventQueue(uint32_t index);