2 * Copyright (c) 2002-2005 The Regents of The University of Michigan
3 * Copyright (c) 2011 Advanced Micro Devices
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
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9 * notice, this list of conditions and the following disclaimer;
10 * redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution;
13 * neither the name of the copyright holders nor the names of its
14 * contributors may be used to endorse or promote products derived from
15 * this software without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 * Authors: Nathan Binkert
34 #include "base/misc.hh"
35 #include "sim/root.hh"
37 Root
*Root::_root
= NULL
;
40 * This function is called periodically by an event in M5 and ensures that
41 * at least as much real time has passed between invocations as simulated time.
42 * If not, the function either sleeps, or if the difference is small enough
48 Time cur_time
, diff
, period
= timeSyncPeriod();
52 diff
= cur_time
- lastTime
;
53 Time remainder
= period
- diff
;
54 if (diff
< period
&& remainder
> _spinThreshold
) {
55 DPRINTF(TimeSync
, "Sleeping to sync with real time.\n");
56 // Sleep until the end of the period, or until a signal.
58 // Refresh the current time.
61 } while (diff
< period
);
63 schedule(&syncEvent
, curTick() + _periodTick
);
67 Root::timeSyncEnable(bool en
)
74 Tick periods
= ((curTick() + _periodTick
- 1) / _periodTick
);
75 Tick nextPeriod
= periods
* _periodTick
;
76 schedule(&syncEvent
, nextPeriod
);
79 deschedule(&syncEvent
);
83 /// Configure the period for time sync events.
85 Root::timeSyncPeriod(Time newPeriod
)
87 bool en
= timeSyncEnabled();
89 _periodTick
= _period
.getTick();
93 /// Set the threshold for time remaining to spin wait.
95 Root::timeSyncSpinThreshold(Time newThreshold
)
97 bool en
= timeSyncEnabled();
98 _spinThreshold
= newThreshold
;
102 Root::Root(RootParams
*p
) : SimObject(p
), _enabled(false),
103 _periodTick(p
->time_sync_period
), syncEvent(this)
105 _period
.setTick(p
->time_sync_period
);
106 _spinThreshold
.setTick(p
->time_sync_spin_threshold
);
108 assert(_root
== NULL
);
116 timeSyncEnable(params()->time_sync_enable
);
120 Root::loadState(Checkpoint
*cp
)
122 timeSyncEnable(params()->time_sync_enable
);
128 static bool created
= false;
130 panic("only one root object allowed!");
134 return new Root(this);