1 #define _GNU_SOURCE
2 #include <errno.h>
3 #include <string.h>
4 #include <pthread.h>
5 #include <stdlib.h>
6 #include <stdio.h>
7 #include <fcntl.h>
8 #include <unistd.h>
9 #include <sys/types.h>
10 #include <sys/syscall.h>
11 #include <sched.h>
12 #include <signal.h>
13 static int loops = 15; // each thread+main will do this amount of loop
14 static int sleepms = 1000; // in each loop, will sleep "sleepms" milliseconds
15 static int burn = 0; // after each sleep, will burn cpu in a tight 'burn' loop
16 static void setup_sigusr_handler(void); // sigusr1 and 2 sigaction setup.
17 
18 static pid_t gettid()
19 {
20 #ifdef __NR_gettid
21    return syscall(__NR_gettid);
22 #else
23    return getpid();
24 #endif
25 }
26 // will be invoked from gdb.
27 static void whoami(char *msg) __attribute__((unused));
28 static void whoami(char *msg)
29 {
30    fprintf(stderr, "pid %ld Thread %ld %s\n", (long) getpid(), (long) gettid(),
31            msg);
32    fflush(stderr);
33 }
34 
35 
36 static void do_burn ()
37 {
38    int i;
39    int loopnr = 0;
40    // one single line for the below, to ensure interrupt on this line.
41    for (i = 0; i < burn; i++) loopnr++;
42 }
43 
44 static int thread_ready = 0;
45 static pthread_cond_t ready = PTHREAD_COND_INITIALIZER;
46 static pthread_mutex_t ready_mutex = PTHREAD_MUTEX_INITIALIZER;
47 static void signal_ready (void)
48 {
49    int rc;
50    rc = pthread_mutex_lock(&ready_mutex);
51    if (rc != 0)
52       fprintf(stderr, "signal_ready lock error %d_n", rc);
53    thread_ready = 1;
54    rc = pthread_cond_signal(&ready);
55    if (rc != 0)
56       fprintf(stderr, "signal_ready signal error %d_n", rc);
57    rc = pthread_mutex_unlock(&ready_mutex);
58    if (rc != 0)
59       fprintf(stderr, "signal_ready unlock error %d_n", rc);
60 }
61 
62 struct spec {
63    char *name;
64    int sleep;
65    int burn;
66    int t;
67 };
68 static struct timeval t[4];
69 static int nr_sleeper_or_burner = 0;
70 static volatile int report_finished = 1;
71 // set to 0 to have no finish msg (as order is non-deterministic)
72 static void *sleeper_or_burner(void *v)
73 {
74    int i = 0;
75    struct spec* s = (struct spec*)v;
76    int ret;
77    fprintf(stderr, "%s ready to sleep and/or burn\n", s->name);
78    fflush (stderr);
79    signal_ready();
80    nr_sleeper_or_burner++;
81 
82    for (i = 0; i < loops; i++) {
83       if (sleepms > 0 && s->sleep) {
84          t[s->t].tv_sec = sleepms / 1000;
85          t[s->t].tv_usec = (sleepms % 1000) * 1000;
86          ret = select (0, NULL, NULL, NULL, &t[s->t]);
87          /* We only expect a timeout result or EINTR from the above. */
88          if (ret != 0 && errno != EINTR)
89             perror("unexpected result from select");
90       }
91       if (burn > 0 && s->burn)
92          do_burn();
93    }
94    if (report_finished) {
95       fprintf(stderr, "%s finished to sleep and/or burn\n", s->name);
96       fflush (stderr);
97    }
98    return NULL;
99 }
100 
101 // wait till a thread signals it is ready
102 static void wait_ready(void)
103 {
104    int rc;
105    rc = pthread_mutex_lock(&ready_mutex);
106    if (rc != 0)
107       fprintf(stderr, "wait_ready lock error %d_n", rc);
108    while (! thread_ready && rc == 0) {
109       rc = pthread_cond_wait(&ready, &ready_mutex);
110       if (rc != 0)
111          fprintf(stderr, "wait_ready wait error %d_n", rc);
112    }
113    thread_ready = 0;
114    rc = pthread_mutex_unlock(&ready_mutex);
115    if (rc != 0)
116       fprintf(stderr, "wait_ready unlock error %d_n", rc);
117 }
118 
119 // We will lock ourselves on one single cpu.
120 // This bypasses the unfairness of the Valgrind scheduler
121 // when a multi-cpu machine has enough cpu to run all the
122 // threads wanting to burn cpu.
123 static void setaffinity(void)
124 {
125 #ifdef VGO_linux
126    cpu_set_t single_cpu;
127    CPU_ZERO(&single_cpu);
128    CPU_SET(1, &single_cpu);
129    (void) sched_setaffinity(0, sizeof(single_cpu), &single_cpu);
130 #endif
131    // GDBTD: equivalent for Darwin ?
132 }
133 
134 int main (int argc, char *argv[])
135 {
136   char *threads_spec;
137   pthread_t ebbr, egll, zzzz;
138   struct spec b, l, p, m;
139   char *some_mem __attribute__((unused)) = malloc(100);
140   if (argc > 5 && atoi(argv[5])) setaffinity();
141   setup_sigusr_handler();
142   if (argc > 1)
143      loops = atoi(argv[1]);
144 
145   if (argc > 2)
146      sleepms = atoi(argv[2]);
147 
148   if (argc > 3)
149      burn = atoll(argv[3]);
150 
151   if (argc > 4)
152      threads_spec = argv[4];
153   else
154      threads_spec = "BSBSBSBS";
155 
156   fprintf(stderr, "loops/sleep_ms/burn/threads_spec/affinity:  %d %d %d %s %d\n",
157           loops, sleepms, burn, threads_spec, argc > 5 && atoi(argv[5]));
158   fflush(stderr);
159 
160   b.name = "Brussels";
161   b.burn = *threads_spec++ == 'B';
162   b.sleep = *threads_spec++ == 'S';
163   b.t = -1;
164   if (b.burn || b.sleep) {
165      b.t = 1;
166      pthread_create(&ebbr, NULL, sleeper_or_burner, &b);
167      wait_ready();
168   }
169 
170   l.name = "London";
171   l.burn = *threads_spec++ == 'B';
172   l.sleep = *threads_spec++ == 'S';
173   l.t = -1;
174   if (l.burn || l.sleep) {
175      l.t = 2;
176      pthread_create(&egll, NULL, sleeper_or_burner, &l);
177      wait_ready();
178   }
179 
180   p.name = "Petaouchnok";
181   p.burn = *threads_spec++ == 'B';
182   p.sleep = *threads_spec++ == 'S';
183   p.t = -1;
184   if (p.burn || p.sleep) {
185      p.t = 3;
186      pthread_create(&zzzz, NULL, sleeper_or_burner, &p);
187      wait_ready();
188   }
189 
190   m.name = "main";
191   m.burn = *threads_spec++ == 'B';
192   m.sleep = *threads_spec++ == 'S';
193   m.t = 0;
194   sleeper_or_burner(&m);
195 
196   if (b.t != -1) pthread_join(ebbr, NULL);
197   if (l.t != -1) pthread_join(egll, NULL);
198   if (p.t != -1) pthread_join(zzzz, NULL);
199 
200   return 0;
201 }
202 
203 static int sigusr1_received = 0;
204 static void sigusr1_handler(int signr)
205 {
206    sigusr1_received++;
207 }
208 static void setup_sigusr_handler(void)
209 {
210    struct sigaction sa;
211    sa.sa_handler = sigusr1_handler;
212    sigemptyset(&sa.sa_mask);
213    sa.sa_flags = 0;
214 
215    if (sigaction (SIGUSR1, &sa, NULL) != 0)
216       perror("sigaction SIGUSR1");
217 
218    sa.sa_handler = SIG_IGN;
219    if (sigaction (SIGUSR2, &sa, NULL) != 0)
220       perror("sigaction SIGUSR2");
221 }
222 
223