gdbserver_tests/sleepers.c

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