scheduler.cc revision 12953:ddfd5e4643a9 
1/*
2 * Copyright 2018 Google, Inc.
3 *
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5 * modification, are permitted provided that the following conditions are
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10 * documentation and/or other materials provided with the distribution;
11 * neither the name of the copyright holders nor the names of its
12 * contributors may be used to endorse or promote products derived from
13 * this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
21 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 *
27 * Authors: Gabe Black
28 */
29
30#include "systemc/core/scheduler.hh"
31
32#include "base/fiber.hh"
33
34namespace sc_gem5
35{
36
37Scheduler::Scheduler() : _numCycles(0), _current(nullptr) {}
38
39void
40Scheduler::initialize()
41{
42    update();
43
44    while (!initList.empty())
45        ready(initList.getNext());
46
47    delta();
48}
49
50void
51Scheduler::runCycles()
52{
53    while (!readyList.empty()) {
54        evaluate();
55        update();
56        delta();
57    }
58}
59
60void
61Scheduler::yield()
62{
63    _current = readyList.getNext();
64    if (!_current) {
65        // There are no more processes, so return control to evaluate.
66        Fiber::primaryFiber()->run();
67    } else {
68        _current->popListNode();
69        // Switch to whatever Fiber is supposed to run this process. All
70        // Fibers which aren't running should be parked at this line.
71        _current->fiber()->run();
72        // If the current process hasn't been started yet, start it. This
73        // should always be true for methods, but may not be true for threads.
74        if (_current && !_current->running())
75            _current->run();
76    }
77}
78
79void
80Scheduler::evaluate()
81{
82    if (!readyList.empty())
83        _numCycles++;
84
85    do {
86        yield();
87    } while (!readyList.empty());
88}
89
90void
91Scheduler::update()
92{
93}
94
95void
96Scheduler::delta()
97{
98}
99
100Scheduler scheduler;
101
102} // namespace sc_gem5
103