checkpoint.py revision 11682:612f75cf36a0 
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36# Authors: Andreas Sandberg
37
38from multiprocessing import Process
39import sys
40import os
41
42import m5
43
44_exit_normal = (
45    "target called exit()",
46    "m5_exit instruction encountered",
47    )
48
49_exit_limit = (
50    "simulate() limit reached",
51    )
52
53_exitcode_done = 0
54_exitcode_fail = 1
55_exitcode_checkpoint = 42
56
57
58def _run_step(name, restore=None, interval=0.5):
59    """
60    Instantiate (optionally from a checkpoint if restore is set to the
61    checkpoitn name) the system and run for interval seconds of
62    simulated time. At the end of the simulation interval, create a
63    checkpoint and exit.
64
65    As this function is intended to run in its own process using the
66    multiprocessing framework, the exit is a true call to exit which
67    terminates the process. Exit codes are used to pass information to
68    the parent.
69    """
70    if restore is not None:
71        m5.instantiate(restore)
72    else:
73        m5.instantiate()
74
75    e = m5.simulate(m5.ticks.fromSeconds(interval))
76    cause = e.getCause()
77    if cause in _exit_limit:
78        m5.checkpoint(name)
79        sys.exit(_exitcode_checkpoint)
80    elif cause in _exit_normal:
81        sys.exit(_exitcode_done)
82    else:
83        print "Test failed: Unknown exit cause: %s" % cause
84        sys.exit(_exitcode_fail)
85
86def run_test(root, interval=0.5, max_checkpoints=5):
87    """
88    Run the simulated system for a fixed amount of time and take a
89    checkpoint, then restore from the same checkpoint and run until
90    the system calls m5 exit.
91    """
92
93    cpt_name = os.path.join(m5.options.outdir, "test.cpt")
94    restore = None
95
96    for cpt_no in range(max_checkpoints):
97        # Create a checkpoint from a separate child process. This enables
98        # us to get back to a (mostly) pristine state and restart
99        # simulation from the checkpoint.
100        p = Process(target=_run_step,
101                    args=(cpt_name, ),
102                    kwargs={
103                "restore" : restore,
104                "interval" : interval,
105                })
106        p.start()
107
108        # Wait for the child to return
109        p.join()
110
111        # Restore from the checkpoint next iteration
112        restore = cpt_name
113
114        if p.exitcode == _exitcode_done:
115            print >> sys.stderr, "Test done."
116            sys.exit(0)
117        elif p.exitcode == _exitcode_checkpoint:
118            pass
119        else:
120            print >> sys.stderr, "Test failed."
121            sys.exit(1)
122
123    # Maximum number of checkpoints reached. Just run full-speed from
124    # now on.
125    m5.instantiate()
126    e = m5.simulate()
127    cause = e.getCause()
128    if cause in _exit_normal:
129        sys.exit(0)
130    else:
131        print "Test failed: Unknown exit cause: %s" % cause
132        sys.exit(1)
133