diff -r 0d38e56356c7 -r 4e2ed6befc63 configs/example/arm/fs_bigLITTLE.py
--- a/configs/example/arm/fs_bigLITTLE.py	Tue Dec 06 17:10:36 2016 +0000
+++ b/configs/example/arm/fs_bigLITTLE.py	Thu Dec 08 11:14:21 2016 +0000
@@ -108,9 +108,10 @@
     return sys
 
 
-def main():
-    parser = argparse.ArgumentParser(
-        description="Generic ARM big.LITTLE configuration")
+def addOptions(parser):
+    """
+    This function adds the commmon big.LITTLE options to the parser.
+    """
 
     parser.add_argument("--restore-from", type=str, default=None,
                         help="Restore from checkpoint")
@@ -138,11 +139,16 @@
                         help="Big CPU clock frequency")
     parser.add_argument("--little-cpu-clock", type=str, default="1GHz",
                         help="Little CPU clock frequency")
+    return parser
 
+
+def build(options):
+    """
+    This function creates and configures all the simObjects of the
+    big.LITTLE system. It returns the root object.
+    """
     m5.ticks.fixGlobalFrequency()
 
-    options = parser.parse_args()
-
     kernel_cmd = [
         "earlyprintk=pl011,0x1c090000",
         "console=ttyAMA0",
@@ -208,20 +214,38 @@
     # Linux device tree
     system.dtb_filename = SysPaths.binary(options.dtb)
 
+    return root
+
+
+def instantiate(checkpoint_path=None):
+    """
+    This function instantiates the system.The checkpoint_path parameter must
+    contain the full path to a checkpoint if we want to restore the
+    simulation from that checkpoint.
+    """
+
     # Get and load from the chkpt or simpoint checkpoint
-    if options.restore_from is not None:
-        m5.instantiate(options.restore_from)
+    if checkpoint_path is not None:
+        m5.util.inform("Restoring from checkpoint %s", checkpoint_path)
+        m5.instantiate(checkpoint_path)
     else:
         m5.instantiate()
 
+
+def run(checkpoint_dir=m5.options.outdir):
+    """
+    This function runs the simulation. The checkpoint_dir parameter specifies
+    the directory we want to write checkpoints into.
+    """
+
     # start simulation (and drop checkpoints when requested)
     while True:
         event = m5.simulate()
         exit_msg = event.getCause()
         if exit_msg == "checkpoint":
             print "Dropping checkpoint at tick %d" % m5.curTick()
-            cpt_dir = os.path.join(m5.options.outdir, "cpt.%d" % m5.curTick())
-            m5.checkpoint(os.path.join(cpt_dir))
+            cpt_dir = os.path.join(checkpoint_dir, "cpt.%d" % m5.curTick())
+            m5.checkpoint(cpt_dir)
             print "Checkpoint done."
         else:
             print exit_msg, " @ ", m5.curTick()
@@ -230,5 +254,15 @@
     sys.exit(event.getCode())
 
 
+def main():
+    parser = argparse.ArgumentParser(
+        description="Generic ARM big.LITTLE configuration")
+    addOptions(parser)
+    options = parser.parse_args()
+    root = build(options)
+    instantiate(options.restore_from)
+    run()
+
+
 if __name__ == "__m5_main__":
     main()