1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
/*
* Copyright (c) 2011-2013 Advanced Micro Devices, Inc.
* Copyright (c) 2013 Mark D. Hill and David A. Wood
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Steve Reinhardt
*/
#include "sim/global_event.hh"
std::mutex BaseGlobalEvent::globalQMutex;
BaseGlobalEvent::BaseGlobalEvent(Priority p, Flags f)
: barrier(numMainEventQueues),
barrierEvent(numMainEventQueues, NULL)
{
}
BaseGlobalEvent::~BaseGlobalEvent()
{
// see GlobalEvent::BarrierEvent::~BarrierEvent() comments
if (barrierEvent[0] != NULL) {
for (int i = 0; i < numMainEventQueues; ++i)
delete barrierEvent[i];
}
}
void BaseGlobalEvent::schedule(Tick when)
{
// This function is scheduling a global event, which actually is a
// set of local events, one event on each eventq. Global events need
// to have a total order. A thread cannot start executing events that
// follow a global event till all other threads have executed that global
// event as well. If global events were not in a total order, a deadlock
// would occur for there will be two threads who would be waiting for
// each other to execute the global events they themselves have executed.
//
// To ensure this total order, we do two things.
// First, before scheduling any global event, a thread needs to acquire
// the lock globalQMutex. This ensures that only one thread can schedule
// global events at any given time.
// Second, the local events corresponding to a global event are always
// first inserted in to the asyncq, irrespective of whether or not the
// thread scheduling the event owns the eventq on which the event is
// being scheduled. Thus global events have the same order in the asyncq
// of each thread. When they are inserted in the actual eventq, the
// comparators in the Event class ensure that the total order is
// maintained.
globalQMutex.lock();
for (int i = 0; i < numMainEventQueues; ++i) {
mainEventQueue[i]->schedule(barrierEvent[i], when, true);
}
globalQMutex.unlock();
}
void BaseGlobalEvent::deschedule()
{
EventQueue *q = curEventQueue();
for (uint32_t i = 0; i < numMainEventQueues; ++i) {
if (barrierEvent[i]->scheduled()) {
curEventQueue(mainEventQueue[i]);
mainEventQueue[i]->deschedule(barrierEvent[i]);
}
}
curEventQueue(q);
}
void BaseGlobalEvent::reschedule(Tick when)
{
// Read the comment in the schedule() function above.
globalQMutex.lock();
for (uint32_t i = 0; i < numMainEventQueues; ++i) {
if (barrierEvent[i]->scheduled())
mainEventQueue[i]->reschedule(barrierEvent[i], when);
else
mainEventQueue[i]->schedule(barrierEvent[i], when, true);
}
globalQMutex.unlock();
}
BaseGlobalEvent::BarrierEvent::~BarrierEvent()
{
// if AutoDelete is set, local events will get deleted in event
// loop, but we need to delete GlobalEvent object too... so let
// the local event in slot 0 do it
if (isFlagSet(AutoDelete) && _globalEvent->barrierEvent[0] == this) {
// set backpointer to NULL so that global event knows not to
// turn around and recursively delete local events
_globalEvent->barrierEvent[0] = NULL;
delete _globalEvent;
}
}
void
GlobalEvent::BarrierEvent::process()
{
// wait for all queues to arrive at barrier, then process event
if (globalBarrier()) {
_globalEvent->process();
}
// second barrier to force all queues to wait for event processing
// to finish before continuing
globalBarrier();
}
void
GlobalSyncEvent::BarrierEvent::process()
{
// wait for all queues to arrive at barrier, then process event
if (globalBarrier()) {
_globalEvent->process();
}
// second barrier to force all queues to wait for event processing
// to finish before continuing
globalBarrier();
curEventQueue()->handleAsyncInsertions();
}
void
GlobalSyncEvent::process()
{
if (repeat) {
schedule(curTick() + repeat);
}
}
const char *
GlobalSyncEvent::description() const
{
return "GlobalSyncEvent";
}
|
