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
|
/* worker_mutex.c -*-C-*-
*
*************************************************************************
*
* Copyright (C) 2009-2016, Intel Corporation
* 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 Intel Corporation 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
* HOLDER 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.
*
* *********************************************************************
*
* PLEASE NOTE: This file is a downstream copy of a file mainitained in
* a repository at cilkplus.org. Changes made to this file that are not
* submitted through the contribution process detailed at
* http://www.cilkplus.org/submit-cilk-contribution will be lost the next
* time that a new version is released. Changes only submitted to the
* GNU compiler collection or posted to the git repository at
* https://bitbucket.org/intelcilkruntime/intel-cilk-runtime.git are
* not tracked.
*
* We welcome your contributions to this open source project. Thank you
* for your assistance in helping us improve Cilk Plus.
**************************************************************************/
#include "worker_mutex.h"
#include "bug.h"
#include "os.h"
#include "stats.h"
/* m->lock == 1 means that mutex M is locked */
#define TRY_ACQUIRE(m) (__cilkrts_xchg(&(m)->lock, 1) == 0)
/* ICC 11.1+ understands release semantics and generates an
ordinary store with a software memory barrier. */
#if __ICC >= 1110
#define RELEASE(m) __sync_lock_release(&(m)->lock)
#else
#define RELEASE(m) __cilkrts_xchg(&(m)->lock, 0)
#endif
void __cilkrts_mutex_init(struct mutex *m)
{
m->owner = 0;
// Use a simple assignment so Inspector doesn't bug us about the
// interlocked exchange doing a read of an uninitialized variable.
// By definition there can't be a race when we're initializing the
// lock...
m->lock = 0;
}
void __cilkrts_mutex_lock(__cilkrts_worker *w, struct mutex *m)
{
int count;
const int maxspin = 1000; /* SWAG */
NOTE_INTERVAL(w, INTERVAL_MUTEX_LOCK);
if (!TRY_ACQUIRE(m)) {
START_INTERVAL(w, INTERVAL_MUTEX_LOCK_SPINNING);
count = 0;
do {
do {
__cilkrts_short_pause();
if (++count >= maxspin) {
STOP_INTERVAL(w, INTERVAL_MUTEX_LOCK_SPINNING);
START_INTERVAL(w, INTERVAL_MUTEX_LOCK_YIELDING);
/* let the OS reschedule every once in a while */
__cilkrts_yield();
STOP_INTERVAL(w, INTERVAL_MUTEX_LOCK_YIELDING);
START_INTERVAL(w, INTERVAL_MUTEX_LOCK_SPINNING);
count = 0;
}
} while (m->lock != 0);
} while (!TRY_ACQUIRE(m));
STOP_INTERVAL(w, INTERVAL_MUTEX_LOCK_SPINNING);
}
CILK_ASSERT(m->owner == 0);
m->owner = w;
}
int __cilkrts_mutex_trylock(__cilkrts_worker *w, struct mutex *m)
{
NOTE_INTERVAL(w, INTERVAL_MUTEX_TRYLOCK);
if (TRY_ACQUIRE(m)) {
CILK_ASSERT(m->owner == 0);
m->owner = w;
return 1;
} else {
return 0;
}
}
void __cilkrts_mutex_unlock(__cilkrts_worker *w, struct mutex *m)
{
CILK_ASSERT(m->owner == w);
m->owner = 0;
RELEASE(m);
}
void __cilkrts_mutex_destroy(__cilkrts_worker *w, struct mutex *m)
{
(void)w; /* unused */
(void)m; /* unused */
}
/* End worker_mutex.c */
|
