diff -r 63da4a862efd -r dfd9f65d2011 configs/common/Simulation.py
--- a/configs/common/Simulation.py	Sun Apr 07 22:48:06 2013 -0500
+++ b/configs/common/Simulation.py	Mon Apr 08 00:17:45 2013 -0500
@@ -100,7 +100,7 @@
     if options.work_cpus_checkpoint_count != None:
         system.work_cpus_ckpt_count = options.work_cpus_checkpoint_count
 
-def findCptDir(options, maxtick, cptdir, testsys):
+def findCptDir(options, cptdir, testsys):
     """Figures out the directory from which the checkpointed state is read.
 
     There are two different ways in which the directories holding checkpoints
@@ -111,9 +111,6 @@
     This function parses through the options to figure out which one of the
     above should be used for selecting the checkpoint, and then figures out
     the appropriate directory.
-
-    It also sets the value of the maximum tick value till which the simulation
-    will run.
     """
 
     from os.path import isdir, exists
@@ -149,10 +146,10 @@
         if cpt_num > len(cpts):
             fatal('Checkpoint %d not found', cpt_num)
 
-        maxtick = maxtick - int(cpts[cpt_num - 1])
+        cpt_starttick = int(cpts[cpt_num - 1])
         checkpoint_dir = joinpath(cptdir, "cpt.%s" % cpts[cpt_num - 1])
 
-    return maxtick, checkpoint_dir
+    return cpt_starttick, checkpoint_dir
 
 def scriptCheckpoints(options, maxtick, cptdir):
     if options.at_instruction or options.simpoint:
@@ -254,15 +251,6 @@
             return exit_event
 
 def run(options, root, testsys, cpu_class):
-    if options.maxtick:
-        maxtick = options.maxtick
-    elif options.maxtime:
-        simtime = m5.ticks.seconds(simtime)
-        print "simulating for: ", simtime
-        maxtick = simtime
-    else:
-        maxtick = m5.MaxTick
-
     if options.checkpoint_dir:
         cptdir = options.checkpoint_dir
     elif m5.options.outdir:
@@ -416,9 +404,24 @@
 
     checkpoint_dir = None
     if options.checkpoint_restore != None:
-        maxtick, checkpoint_dir = findCptDir(options, maxtick, cptdir, testsys)
+        cpt_starttick, checkpoint_dir = findCptDir(options, cptdir, testsys)
     m5.instantiate(checkpoint_dir)
 
+    # Handle the maxtick settings now that tick frequency was resolved
+    # during system instantiation
+    if options.maxtick:
+        maxtick = options.maxtick
+    elif options.maxtime:
+        maxtick = m5.ticks.fromSeconds(options.maxtime)
+        print "Simulating %f seconds (until tick %d)" % \
+            (options.maxtime, maxtick)
+    else:
+        maxtick = m5.MaxTick
+
+    if options.checkpoint_restore != None and maxtick < cpt_starttick:
+        fatal("Bad maxtick (%d) specified: " +
+              "Checkpoint starts starts from tick: %d", maxtick, cpt_starttick)
+
     if options.standard_switch or cpu_class:
         if options.standard_switch:
             print "Switch at instruction count:%s" % \
diff -r 63da4a862efd -r dfd9f65d2011 configs/common/Options.py
--- a/configs/common/Options.py	Sun Apr 07 22:48:06 2013 -0500
+++ b/configs/common/Options.py	Mon Apr 08 00:17:45 2013 -0500
@@ -71,9 +71,10 @@
                       number of programs.""")
 
     # Run duration options
-    parser.add_option("-m", "--maxtick", type="int", default=m5.MaxTick,
+    parser.add_option("-m", "--maxtick", type="int", default=None,
                       metavar="T", help="Stop after T ticks")
-    parser.add_option("--maxtime", type="float")
+    parser.add_option("--maxtime", type="float",
+                      help="Run to the specified simulated time in seconds")
     parser.add_option("-I", "--maxinsts", action="store", type="int",
                       default=None, help="""Total number of instructions to
                                             simulate (default: run forever)""")