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 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_sys(),
  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