switcheroo.py revision 11802:be62996c95d1 
1# Copyright (c) 2012 ARM Limited
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36# Authors: Andreas Sandberg
37
38import m5
39import _m5
40from m5.objects import *
41m5.util.addToPath('../configs/')
42from common.Caches import *
43
44class Sequential:
45    """Sequential CPU switcher.
46
47    The sequential CPU switches between all CPUs in a system in
48    order. The CPUs in the system must have been prepared for
49    switching, which in practice means that only one CPU is switched
50    in. base_config.BaseFSSwitcheroo can be used to create such a
51    system.
52    """
53    def __init__(self, cpus):
54        self.first_cpu = None
55        for (cpuno, cpu) in enumerate(cpus):
56            if not cpu.switched_out:
57                if self.first_cpu != None:
58                    fatal("More than one CPU is switched in");
59                self.first_cpu = cpuno
60
61        if self.first_cpu == None:
62            fatal("The system contains no switched in CPUs")
63
64        self.cur_cpu = self.first_cpu
65        self.cpus = cpus
66
67    def next(self):
68        self.cur_cpu = (self.cur_cpu + 1) % len(self.cpus)
69        return self.cpus[self.cur_cpu]
70
71    def first(self):
72        return self.cpus[self.first_cpu]
73
74def run_test(root, switcher=None, freq=1000, verbose=False):
75    """Test runner for CPU switcheroo tests.
76
77    The switcheroo test runner is used to switch CPUs in a system that
78    has been prepared for CPU switching. Such systems should have
79    multiple CPUs when they are instantiated, but only one should be
80    switched in. Such configurations can be created using the
81    base_config.BaseFSSwitcheroo class.
82
83    A CPU switcher object is used to control switching. The default
84    switcher sequentially switches between all CPUs in a system,
85    starting with the CPU that is currently switched in.
86
87    Unlike most other test runners, this one automatically configures
88    the memory mode of the system based on the first CPU the switcher
89    reports.
90
91    Keyword Arguments:
92      switcher -- CPU switcher implementation. See Sequential for
93                  an example implementation.
94      period -- Switching frequency in Hz.
95      verbose -- Enable output at each switch (suppressed by default).
96    """
97
98    if switcher == None:
99        switcher = Sequential(root.system.cpu)
100
101    current_cpu = switcher.first()
102    system = root.system
103    system.mem_mode = type(current_cpu).memory_mode()
104
105    # Suppress "Entering event queue" messages since we get tons of them.
106    # Worse yet, they include the timestamp, which makes them highly
107    # variable and unsuitable for comparing as test outputs.
108    _m5.core.cvar.want_info = verbose
109
110    # instantiate configuration
111    m5.instantiate()
112
113    # Determine the switching period, this has to be done after
114    # instantiating the system since the time base must be fixed.
115    period = m5.ticks.fromSeconds(1.0 / freq)
116    while True:
117        exit_event = m5.simulate(period)
118        exit_cause = exit_event.getCause()
119
120        if exit_cause == "simulate() limit reached":
121            next_cpu = switcher.next()
122
123            if verbose:
124                print "Switching CPUs..."
125                print "Next CPU: %s" % type(next_cpu)
126            m5.drain()
127            if current_cpu != next_cpu:
128                m5.switchCpus(system, [ (current_cpu, next_cpu) ],
129                              verbose=verbose)
130            else:
131                print "Source CPU and destination CPU are the same, skipping..."
132            current_cpu = next_cpu
133        elif exit_cause == "target called exit()" or \
134                exit_cause == "m5_exit instruction encountered":
135
136            sys.exit(0)
137        else:
138            print "Test failed: Unknown exit cause: %s" % exit_cause
139            sys.exit(1)
140