switcheroo.py revision 9447 
1# Copyright (c) 2012 ARM Limited
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3#
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35#
36# Authors: Andreas Sandberg
37
38import m5
39from m5.objects import *
40m5.util.addToPath('../configs/common')
41from Caches import *
42
43def _memMode(cclass):
44    if cclass == AtomicSimpleCPU:
45        return "atomic", m5.objects.params.atomic
46    else:
47        return "timing", m5.objects.params.timing
48
49class Sequential:
50    """Sequential CPU switcher.
51
52    The sequential CPU switches between all CPUs in a system in
53    order. The CPUs in the system must have been prepared for
54    switching, which in practice means that only one CPU is switched
55    in. base_config.BaseFSSwitcheroo can be used to create such a
56    system.
57    """
58    def __init__(self, cpus):
59        self.first_cpu = None
60        for (cpuno, cpu) in enumerate(cpus):
61            if not cpu.switched_out:
62                if self.first_cpu != None:
63                    fatal("More than one CPU is switched in");
64                self.first_cpu = cpuno
65
66        if self.first_cpu == None:
67            fatal("The system contains no switched in CPUs")
68
69        self.cur_cpu = self.first_cpu
70        self.cpus = cpus
71
72    def next(self):
73        self.cur_cpu = (self.cur_cpu + 1) % len(self.cpus)
74        return self.cpus[self.cur_cpu]
75
76    def first(self):
77        return self.cpus[self.first_cpu]
78
79def run_test(root, switcher=None, freq=1000):
80    """Test runner for CPU switcheroo tests.
81
82    The switcheroo test runner is used to switch CPUs in a system that
83    has been prepared for CPU switching. Such systems should have
84    multiple CPUs when they are instantiated, but only one should be
85    switched in. Such configurations can be created using the
86    base_config.BaseFSSwitcheroo class.
87
88    A CPU switcher object is used to control switching. The default
89    switcher sequentially switches between all CPUs in a system,
90    starting with the CPU that is currently switched in.
91
92    Unlike most other test runners, this one automatically configures
93    the memory mode of the system based on the first CPU the switcher
94    reports.
95
96    Keyword Arguments:
97      switcher -- CPU switcher implementation. See Sequential for
98                  an example implementation.
99      period -- Switching frequency in Hz.
100    """
101
102    if switcher == None:
103        switcher = Sequential(root.system.cpu)
104
105    current_cpu = switcher.first()
106    system = root.system
107    system.mem_mode = _memMode(type(current_cpu))[0]
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            print "Switching CPUs..."
123            print "Next CPU: %s" % type(next_cpu)
124            m5.drain(system)
125            system.setMemoryMode(_memMode(type(next_cpu))[1])
126            if current_cpu != next_cpu:
127                m5.switchCpus([ (current_cpu, next_cpu) ])
128            else:
129                print "Source CPU and destination CPU are the same, skipping..."
130            m5.resume(system)
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