-
Notifications
You must be signed in to change notification settings - Fork 0
/
lcr.c
227 lines (185 loc) · 5.97 KB
/
lcr.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
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
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
/**
* lcr.c
*
* March 13, 2014
*
* @author Mira Leung
*
* Usage:
* mpiexec -n <N PROCESSES> ./lcr <RELATIVELY COPRIME NUMBER TO N PROCESSES> [ 1 ] for randomly-assigned uids
*
* An implementation of Lelann/Chang-Roberts', except that it checks for the
* minimum uid seen so far, instead of against its own.
* Unidirectional ring.
*
*/
#include "mpi.h"
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <fgmpi.h>
// Tags
#define TAG_PHASE1 2
#define TAG_ELECTION 3
#define TAG_NRECV 4
#define TAG_NSENT 5
#define TAG_MSGNUM 6
#define SIZE_MSG 2
// Process states
typedef enum { NONINIT, INIT, LEADER } process_state; // A NONINIT process lost the election
int ceiling_log2(unsigned long long x);
int gcd(int size, int pnum);
/** FG-MPI Boilerplate begins **/
int lcr(int argc, char* argv[]);
FG_ProcessPtr_t binding_func(int argc, char** argv, int rank) {
return (&lcr);
}
FG_MapPtr_t map_lookup(int argc, char** argv, char* str) {
return (&binding_func);
}
int main(int argc, char *argv[]) {
FGmpiexec(&argc, &argv, &map_lookup);
return 0;
}
/** FG-MPI Boilerplate ends **/
/**
* Main
*/
int lcr(int argc, char *argv[]) {
if (argc != 2 && argc != 3 && argc != 4) {
printf("Usage: ./lcr [ -v ] <Process number>\n");
exit(1);
}
int pnum;
int verbose = 0;
int rand_flag = 0;
if (argc == 4) {
if (!strcmp(argv[1], "-v")) {
pnum = atoi(argv[2]);
rand_flag = atoi(argv[3]), verbose = 1;
} else if (!strcmp(argv[2], "-v")) {
pnum = atoi(argv[1]);
rand_flag = atoi(argv[3]), verbose = 1;
} else if (!strcmp(argv[3], "-v")) {
pnum = atoi(argv[1]);
rand_flag = atoi(argv[2]), verbose = 1;
}
} else if (argc == 3) {
if (!strcmp(argv[1], "-v")) {
pnum = atoi(argv[2]);
verbose = 1;
} else if (!strcmp(argv[2], "-v")) {
pnum = atoi(argv[1]);
verbose = 1;
} else {
pnum = atoi(argv[1]);
rand_flag = atoi(argv[2]);
}
} else if (argc == 2)
pnum = atoi(argv[1]);
int rank, size, uid;
int tag, max_so_far;
int recv_buf[2];
int lnum_sent = 0, lnum_recv = 0;
int tnum_sent = 0, tnum_recv = 0;
process_state my_state = INIT;
MPI_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &size);
MPI_Request request;
MPI_Status status;
if (pnum <= size || (int) pnum/size < 7 || gcd(size, pnum) != 1) {
printf("Usage: pnum is %d must be at least 7 times larger than and relatively coprime to size.\n", pnum);
exit(1);
}
int send_neighbour = (rank+1) % size, recv_neighbour = rank - 1;
if (!rank) recv_neighbour = size - 1;
srand(time(NULL)+rank);
uid = (rank+1)*(pnum % size);
if (rand_flag) uid = (rand() % pnum);
max_so_far = uid;
tag = TAG_PHASE1;
if (my_state == INIT) {
MPI_Isend(&max_so_far, SIZE_MSG, MPI_INT, send_neighbour, tag, MPI_COMM_WORLD, &request);
lnum_sent++;
}
// Everyone is an initiator by default
while (my_state == INIT) {
MPI_Recv(&recv_buf, SIZE_MSG, MPI_INT, recv_neighbour, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
lnum_recv++;
// Got an election message or a smaller uid than the least seen so far, so I know I lost
if (status.MPI_TAG == TAG_ELECTION || recv_buf[0] > max_so_far) {
max_so_far = recv_buf[0];
my_state = NONINIT; // lost the election
// forward the message, and break;
MPI_Isend(recv_buf, SIZE_MSG, MPI_INT, send_neighbour, status.MPI_TAG, MPI_COMM_WORLD, &request);
lnum_sent++;
break;
}
// Got my own uid back; I'm the leader
if (recv_buf[0] == uid) {
max_so_far = uid;
my_state = LEADER;
tag = TAG_ELECTION;
MPI_Isend(&uid, SIZE_MSG, MPI_INT, send_neighbour, tag, MPI_COMM_WORLD, &request);
lnum_sent++;
}
}
// Non-candidates forward messages
while (1) {
MPI_Recv(recv_buf, SIZE_MSG, MPI_INT, recv_neighbour, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
lnum_recv++;
if (my_state == NONINIT && status.MPI_TAG == TAG_ELECTION) {
if (recv_buf[0] > max_so_far) max_so_far = recv_buf[0];
MPI_Isend(recv_buf, SIZE_MSG, MPI_INT, send_neighbour, status.MPI_TAG, MPI_COMM_WORLD, &request);
lnum_sent++;
break;
} else if (my_state == LEADER && recv_buf[0] == uid && status.MPI_TAG == TAG_ELECTION) {
if (recv_buf[0] > max_so_far) max_so_far = recv_buf[0];
break;
}
MPI_Isend(recv_buf, SIZE_MSG, MPI_INT, send_neighbour, status.MPI_TAG, MPI_COMM_WORLD, &request);
lnum_sent++;
}
if (verbose) printf("rank=%d, id=%d, leader=%d, mrcvd=%d, msent=%d\n", rank, uid, max_so_far == uid, lnum_recv, lnum_sent);
// Non-leaders, send your local message totals
int msgBuf[2] = { lnum_recv, lnum_sent };
if (my_state != LEADER) {
MPI_Recv(recv_buf, SIZE_MSG, MPI_INT, recv_neighbour, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
if (status.MPI_TAG == TAG_MSGNUM) msgBuf[0] += recv_buf[0], msgBuf[1] += recv_buf[1];
}
MPI_Isend(msgBuf, SIZE_MSG, MPI_INT, send_neighbour, TAG_MSGNUM, MPI_COMM_WORLD, &request);
// Leader receives/prints total number of messages sent and received
if (my_state == LEADER) {
MPI_Recv(recv_buf, SIZE_MSG, MPI_INT, recv_neighbour, TAG_MSGNUM, MPI_COMM_WORLD, &status);
tnum_recv = recv_buf[0]; tnum_sent = recv_buf[1];
printf("Leader: rank=%d, id=%d, trcvd=%d, tsent=%d\n", rank, uid, tnum_recv, tnum_sent);
}
MPI_Finalize();
return 0;
}
int gcd(int size, int pnum) {
int k = size, m = pnum;
while (k != m) {
if (k > m) k = k-m;
else m = m-k;
}
return k;
}
int ceiling_log2(unsigned long long x) {
static const unsigned long long t[6] = {
0xFFFFFFFF00000000ull,
0x00000000FFFF0000ull,
0x000000000000FF00ull,
0x00000000000000F0ull,
0x000000000000000Cull,
0x0000000000000002ull
};
int y = (((x & (x - 1)) == 0) ? 0 : 1);
int j = 32, i;
for (i = 0; i < 6; i++) {
int k = (((x & t[i]) == 0) ? 0 : j);
y += k, x >>= k, j >>= 1;
}
return y;
}