switcheroo.py revision 9521 
1# Copyright (c) 2012 ARM Limited
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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):
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    """
95
96    if switcher == None:
97        switcher = Sequential(root.system.cpu)
98
99    current_cpu = switcher.first()
100    system = root.system
101    system.mem_mode = type(current_cpu).memory_mode()
102
103    # instantiate configuration
104    m5.instantiate()
105
106    # Determine the switching period, this has to be done after
107    # instantiating the system since the time base must be fixed.
108    period = m5.ticks.fromSeconds(1.0 / freq)
109    while True:
110        exit_event = m5.simulate(period)
111        exit_cause = exit_event.getCause()
112
113        if exit_cause == "simulate() limit reached":
114            next_cpu = switcher.next()
115
116            print "Switching CPUs..."
117            print "Next CPU: %s" % type(next_cpu)
118            m5.drain(system)
119            if current_cpu != next_cpu:
120                m5.switchCpus(system, [ (current_cpu, next_cpu) ],
121                              do_drain=False)
122            else:
123                print "Source CPU and destination CPU are the same, skipping..."
124            m5.resume(system)
125            current_cpu = next_cpu
126        elif exit_cause == "target called exit()" or \
127                exit_cause == "m5_exit instruction encountered":
128
129            sys.exit(0)
130        else:
131            print "Test failed: Unknown exit cause: %s" % exit_cause
132            sys.exit(1)
133