tests/kernel/test-tsc-sync.c

   1 /* test-tsc-sync.c
   2  *
   3  * Test TSC sync
   4  */
   5
   6
   7 #include <linux/module.h>
   8 #include <linux/timer.h>
   9 #include <asm/timex.h>
  10 #include <linux/jiffies.h>
  11
  12 static DEFINE_PER_CPU(cycles_t, count) = 0;
  13
  14 static struct timer_list test_timer;
  15
  16 /* IPI called on each CPU. */
  17 static void test_each(void *info)
  18 {
  19         __get_cpu_var(count) = get_cycles();
  20 }
  21
  22 static void do_test_timer(unsigned long data)
  23 {
  24         int cpu;
  25
  26         /* Increment the counters */
  27         on_each_cpu(test_each, NULL, 0, 1);
  28         /* Read all the counters */
  29         printk("Counters read from CPU %d\n", smp_processor_id());
  30         for_each_online_cpu(cpu) {
  31                 printk("Read : CPU %d, count %llu\n", cpu,
  32                         per_cpu(count, cpu));
  33         }
  34         del_timer(&test_timer);
  35         test_timer.expires = jiffies + 1000;
  36         add_timer(&test_timer);
  37 }
  38
  39 static int __init test_init(void)
  40 {
  41         /* initialize the timer that will increment the counter */
  42         init_timer(&test_timer);
  43         test_timer.function = do_test_timer;
  44         test_timer.expires = jiffies + 1;
  45         add_timer(&test_timer);
  46
  47         return 0;
  48 }
  49
  50 static void __exit test_exit(void)
  51 {
  52         del_timer_sync(&test_timer);
  53 }
  54
  55 module_init(test_init);
  56 module_exit(test_exit);
  57
  58 MODULE_LICENSE("GPL");
  59 MODULE_AUTHOR("Mathieu Desnoyers");
  60 MODULE_DESCRIPTION("sync tsc test");
  61