switcheroo.py revision 10912 
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36# Authors: Andreas Sandberg
37
38import m5
39from m5.objects import *
40m5.util.addToPath('../configs/common')
41from Caches import *
42
43class Sequential:
44    """Sequential CPU switcher.
45
46    The sequential CPU switches between all CPUs in a system in
47    order. The CPUs in the system must have been prepared for
48    switching, which in practice means that only one CPU is switched
49    in. base_config.BaseFSSwitcheroo can be used to create such a
50    system.
51    """
52    def __init__(self, cpus):
53        self.first_cpu = None
54        for (cpuno, cpu) in enumerate(cpus):
55            if not cpu.switched_out:
56                if self.first_cpu != None:
57                    fatal("More than one CPU is switched in");
58                self.first_cpu = cpuno
59
60        if self.first_cpu == None:
61            fatal("The system contains no switched in CPUs")
62
63        self.cur_cpu = self.first_cpu
64        self.cpus = cpus
65
66    def next(self):
67        self.cur_cpu = (self.cur_cpu + 1) % len(self.cpus)
68        return self.cpus[self.cur_cpu]
69
70    def first(self):
71        return self.cpus[self.first_cpu]
72
73def run_test(root, switcher=None, freq=1000, verbose=False):
74    """Test runner for CPU switcheroo tests.
75
76    The switcheroo test runner is used to switch CPUs in a system that
77    has been prepared for CPU switching. Such systems should have
78    multiple CPUs when they are instantiated, but only one should be
79    switched in. Such configurations can be created using the
80    base_config.BaseFSSwitcheroo class.
81
82    A CPU switcher object is used to control switching. The default
83    switcher sequentially switches between all CPUs in a system,
84    starting with the CPU that is currently switched in.
85
86    Unlike most other test runners, this one automatically configures
87    the memory mode of the system based on the first CPU the switcher
88    reports.
89
90    Keyword Arguments:
91      switcher -- CPU switcher implementation. See Sequential for
92                  an example implementation.
93      period -- Switching frequency in Hz.
94      verbose -- Enable output at each switch (suppressed by default).
95    """
96
97    if switcher == None:
98        switcher = Sequential(root.system.cpu)
99
100    current_cpu = switcher.first()
101    system = root.system
102    system.mem_mode = type(current_cpu).memory_mode()
103
104    # Suppress "Entering event queue" messages since we get tons of them.
105    # Worse yet, they include the timestamp, which makes them highly
106    # variable and unsuitable for comparing as test outputs.
107    m5.internal.core.cvar.want_info = verbose
108
109    # instantiate configuration
110    m5.instantiate()
111
112    # Determine the switching period, this has to be done after
113    # instantiating the system since the time base must be fixed.
114    period = m5.ticks.fromSeconds(1.0 / freq)
115    while True:
116        exit_event = m5.simulate(period)
117        exit_cause = exit_event.getCause()
118
119        if exit_cause == "simulate() limit reached":
120            next_cpu = switcher.next()
121
122            if verbose:
123                print "Switching CPUs..."
124                print "Next CPU: %s" % type(next_cpu)
125            m5.drain()
126            if current_cpu != next_cpu:
127                m5.switchCpus(system, [ (current_cpu, next_cpu) ],
128                              verbose=verbose)
129            else:
130                print "Source CPU and destination CPU are the same, skipping..."
131            current_cpu = next_cpu
132        elif exit_cause == "target called exit()" or \
133                exit_cause == "m5_exit instruction encountered":
134
135            sys.exit(0)
136        else:
137            print "Test failed: Unknown exit cause: %s" % exit_cause
138            sys.exit(1)
139