git.ozlabs.org Git - ccan/blob - ccan/lbalance/tools/lbalance.c

   1 #include <ccan/lbalance/lbalance.h>
   2 #include <ccan/lbalance/lbalance.c>
   3 #include <ccan/time/time.h>
   4 #include <ccan/jmap/jmap_type.h>
   5 #include <stdio.h>
   6 #include <err.h>
   7
   8 /* Defines struct jmap_task. */
   9 JMAP_DEFINE_UINTIDX_TYPE(struct lbalance_task, task);
  10
  11 /* Figure out how many loops we need to run for about 1 second. */
  12 static unsigned long burn_count;
  13
  14 static void calibrate_burn_cpu(void)
  15 {
  16         struct timeval start = time_now();
  17
  18         while (time_less(time_now(), time_add(start, time_from_msec(1000))))
  19                 burn_count++;
  20         printf("Burn count = %lu\n", burn_count);
  21 }
  22
  23 static void burn_cpu(void)
  24 {
  25         unsigned int i, after = 0;
  26         struct timeval start = time_now();
  27
  28         /* We do a loop similar to the calibrate_burn_cpu loop. */
  29         for (i = 0; i < burn_count; i++) {
  30                 after += time_less(time_now(),
  31                                    time_add(start, time_from_msec(1000)));
  32         }
  33         /* We use the result so the compiler can't discard it. */
  34         exit(after);
  35 }
  36
  37 static pid_t spawn(char *args[])
  38 {
  39         pid_t pid = fork();
  40
  41         if (pid == -1)
  42                 err(1, "forking");
  43         if (pid == 0) {
  44                 if (!args[0])
  45                         burn_cpu();
  46                 execvp(args[0], args);
  47                 err(1, "exec failed");
  48         }
  49         return pid;
  50 }
  51
  52 int main(int argc, char *argv[])
  53 {
  54         unsigned int i, num, fixed_target = 0, num_done = 0, num_running = 0;
  55         struct lbalance *lb;
  56         struct jmap_task *tasks = jmap_task_new();
  57
  58         if (argc < 2) {
  59                 fprintf(stderr,
  60                         "Usage: lbalance --fixed=<num> <num> [<command>...]\n"
  61                         "OR: lbalance <num> [<command>...]\n");
  62                 exit(1);
  63         }
  64
  65         if (strncmp(argv[1], "--fixed=", strlen("--fixed=")) == 0) {
  66                 fixed_target = atoi(argv[1] + strlen("--fixed="));
  67                 if (!fixed_target)
  68                         errx(1, "Need positive number after --fixed");
  69                 argv++;
  70                 argc--;
  71                 lb = NULL;
  72         } else {
  73                 lb = lbalance_new();
  74         }
  75         num = atoi(argv[1]);
  76         argv++;
  77         argc--;
  78
  79         if (!argv[1])
  80                 calibrate_burn_cpu();
  81
  82         while (num_done < num) {
  83                 unsigned int j, target = fixed_target;
  84                 struct lbalance_task *task;
  85                 struct rusage ru;
  86                 pid_t pid;
  87
  88                 if (lb) {
  89                         target = lbalance_target(lb);
  90                         printf("(%u)", target);
  91                 }
  92
  93                 while (num_running < target && num_done + num_running < num) {
  94                         pid = spawn(argv+1);
  95                         if (lb)
  96                                 task = lbalance_task_new(lb);
  97                         else
  98                                 task = (void *)1;
  99                         jmap_task_add(tasks, pid, task);
 100                         num_running++;
 101                         printf("+"); fflush(stdout);
 102                 }
 103
 104                 /* Now wait for something to die! */
 105                 pid = wait3(NULL, 0, &ru);
 106                 task = jmap_task_get(tasks, pid);
 107                 if (lb)
 108                         lbalance_task_free(task, &ru);
 109                 num_done++;
 110                 num_running--;
 111                 printf("-"); fflush(stdout);
 112         }
 113         printf("\n");
 114         if (lb)
 115                 lbalance_free(lb);
 116         return 0;
 117 }