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

2 files changed, 6 insertions, 3 deletions

diff --git a/src/cpu/base.cc b/src/cpu/base.cc
index 25fe9bf97..3078472fd 100644
--- a/src/cpu/base.cc
+++ b/src/cpu/base.cc
@@ -13,6 +13,8 @@
  *
  * Copyright (c) 2002-2005 The Regents of The University of Michigan
  * Copyright (c) 2011 Regents of the University of California
+ * 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
@@ -569,7 +571,7 @@ void
 BaseCPU::scheduleInstStop(ThreadID tid, Counter insts, const char *cause)
 {
     const Tick now(comInstEventQueue[tid]->getCurTick());
-    Event *event(new SimLoopExitEvent(cause, 0));
+    Event *event(new LocalSimLoopExitEvent(cause, 0));
 
     comInstEventQueue[tid]->schedule(event, now + insts);
 }
@@ -578,7 +580,7 @@ void
 BaseCPU::scheduleLoadStop(ThreadID tid, Counter loads, const char *cause)
 {
     const Tick now(comLoadEventQueue[tid]->getCurTick());
-    Event *event(new SimLoopExitEvent(cause, 0));
+    Event *event(new LocalSimLoopExitEvent(cause, 0));
 
     comLoadEventQueue[tid]->schedule(event, now + loads);
 }
diff --git a/src/cpu/kvm/base.cc b/src/cpu/kvm/base.cc
index d03657a88..589964a32 100644
--- a/src/cpu/kvm/base.cc
+++ b/src/cpu/kvm/base.cc
@@ -506,7 +506,8 @@ BaseKvmCPU::tick()
 
       case RunningServiceCompletion:
       case Running: {
-          Tick ticksToExecute(mainEventQueue.nextTick() - curTick());
+          EventQueue *q = curEventQueue();
+          Tick ticksToExecute(q->nextTick() - curTick());
 
           // We might need to update the KVM state.
           syncKvmState();