forked from pabuhr/concurrent-locking
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Tsay.c
70 lines (55 loc) · 2.01 KB
/
Tsay.c
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
// Yih-Kuen Tsay, Deriving a Scalable Algorithm for Mutual Exclusion,
// Distributed Computing, Lecture Notes in Computer Science Volume 1499, 1998, pp 393-407
enum Intent { DontWantIn, WantIn };
static TYPE PAD1 CALIGN __attribute__(( unused )); // protect further false sharing
static VTYPE intents[2] CALIGN = { DontWantIn, DontWantIn }, last CALIGN;
static TYPE PAD2 CALIGN __attribute__(( unused )); // protect further false sharing
#define inv( c ) ((c) ^ 1)
static void * Worker( void * arg ) {
TYPE id = (size_t)arg;
uint64_t entry;
#ifdef FAST
unsigned int cnt = 0, oid = id;
#endif // FAST
int other = inv( id ); // int is better than TYPE
for ( int r = 0; r < RUNS; r += 1 ) {
RTYPE randomThreadChecksum = 0;
for ( entry = 0; stop == 0; entry += 1 ) {
intents[id] = WantIn; // entry protocol
last = id; // RACE
Fence(); // force store before more loads
if ( FASTPATH( intents[other] != DontWantIn ) ) // local spin
while ( last == id ) Pause(); // busy wait
randomThreadChecksum += CriticalSection( id );
intents[id] = DontWantIn; // exit protocol
last = id;
#ifdef FAST
id = startpoint( cnt ); // different starting point each experiment
other = inv( id );
cnt = cycleUp( cnt, NoStartPoints );
#endif // FAST
} // for
__sync_fetch_and_add( &sumOfThreadChecksums, randomThreadChecksum );
#ifdef FAST
id = oid;
other = inv( id );
#endif // FAST
entries[r][id] = entry;
__sync_fetch_and_add( &Arrived, 1 );
while ( stop != 0 ) Pause();
__sync_fetch_and_add( &Arrived, -1 );
} // for
return NULL;
} // Worker
void __attribute__((noinline)) ctor() {
if ( N != 2 ) {
printf( "\nUsage: N=%zd must be 2\n", N );
exit( EXIT_FAILURE);
} // if
} // ctor
void __attribute__((noinline)) dtor() {
} // dtor
// Local Variables: //
// tab-width: 4 //
// compile-command: "gcc -Wall -Wextra -std=gnu11 -O3 -DNDEBUG -fno-reorder-functions -DPIN -DAlgorithm=Tsay Harness.c -lpthread -lm -D`hostname` -DCFMT -DCNT=0" //
// End: //