2 * Copyright (c) 2002-2005 The Regents of The University of Michigan
3 * Copyright (c) 2011 Advanced Micro Devices, Inc.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met: redistributions of source code must retain the above copyright
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
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 * Authors: Nathan Binkert
34 #include "base/misc.hh"
35 #include "debug/TimeSync.hh"
36 #include "sim/root.hh"
38 Root
*Root::_root
= NULL
;
41 * This function is called periodically by an event in M5 and ensures that
42 * at least as much real time has passed between invocations as simulated time.
43 * If not, the function either sleeps, or if the difference is small enough
49 Time cur_time
, diff
, period
= timeSyncPeriod();
53 diff
= cur_time
- lastTime
;
54 Time remainder
= period
- diff
;
55 if (diff
< period
&& remainder
> _spinThreshold
) {
56 DPRINTF(TimeSync
, "Sleeping to sync with real time.\n");
57 // Sleep until the end of the period, or until a signal.
59 // Refresh the current time.
62 } while (diff
< period
);
64 schedule(&syncEvent
, curTick() + _periodTick
);
68 Root::timeSyncEnable(bool en
)
75 Tick periods
= ((curTick() + _periodTick
- 1) / _periodTick
);
76 Tick nextPeriod
= periods
* _periodTick
;
77 schedule(&syncEvent
, nextPeriod
);
80 deschedule(&syncEvent
);
84 /// Configure the period for time sync events.
86 Root::timeSyncPeriod(Time newPeriod
)
88 bool en
= timeSyncEnabled();
90 _periodTick
= _period
.getTick();
94 /// Set the threshold for time remaining to spin wait.
96 Root::timeSyncSpinThreshold(Time newThreshold
)
98 bool en
= timeSyncEnabled();
99 _spinThreshold
= newThreshold
;
103 Root::Root(RootParams
*p
) : SimObject(p
), _enabled(false),
104 _periodTick(p
->time_sync_period
), syncEvent(this)
106 _period
.setTick(p
->time_sync_period
);
107 _spinThreshold
.setTick(p
->time_sync_spin_threshold
);
109 assert(_root
== NULL
);
117 timeSyncEnable(params()->time_sync_enable
);
121 Root::loadState(Checkpoint
*cp
)
123 timeSyncEnable(params()->time_sync_enable
);
129 static bool created
= false;
131 panic("only one root object allowed!");
135 return new Root(this);