trunk/tests/kernel/test-cmpxchg.c

   1 /* test-cmpxchg.c
   2  *
   3  * Test time spent in a LTTng instrumentation probe.
   4  */
   5
   6
   7 #include <linux/jiffies.h>
   8 #include <linux/compiler.h>
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11
  12 #define NR_LOOPS 20000
  13
  14 volatile int test_val = 100;
  15
  16
  17 static inline void do_test(void)
  18 {
  19         int val, ret;
  20
  21         val = test_val;
  22
  23         ret = cmpxchg(&test_val, val, val+1);
  24 }
  25
  26 //void (*fct)(void) = do_test;
  27
  28 static int ltt_test_init(void)
  29 {
  30         unsigned int i;
  31         cycles_t time1, time2, time;
  32         cycles_t max_time = 0, min_time = 18446744073709551615ULL; /* (2^64)-1 */
  33         cycles_t tot_time = 0;
  34         unsigned long flags;
  35         printk(KERN_ALERT "test init\n");
  36
  37         local_irq_save(flags);
  38         time1 = get_cycles();
  39         for(i=0; i<NR_LOOPS; i++) {
  40                 //for(int j=0; j<10; j++) {
  41                 do_test();
  42                 //}
  43                 //max_time = max(max_time, time);
  44                 //min_time = min(min_time, time);
  45                 //printk("val : %d\n", test_val);
  46         }
  47         time2 = get_cycles();
  48         local_irq_restore(flags);
  49         time = time2 - time1;
  50         tot_time += time;
  51
  52         printk(KERN_ALERT "test results : time for cmpxchg\n");
  53         printk(KERN_ALERT "number of loops : %d\n", NR_LOOPS);
  54         printk(KERN_ALERT "total time : %llu\n", tot_time);
  55         //printk(KERN_ALERT "min : %llu\n", min_time);
  56         //printk(KERN_ALERT "max : %llu\n", max_time);
  57
  58         printk(KERN_ALERT "test end\n");
  59
  60         return -EAGAIN; /* Fail will directly unload the module */
  61 }
  62
  63 static void ltt_test_exit(void)
  64 {
  65         printk(KERN_ALERT "test exit\n");
  66 }
  67
  68 module_init(ltt_test_init)
  69 module_exit(ltt_test_exit)
  70
  71 MODULE_LICENSE("GPL");
  72 MODULE_AUTHOR("Mathieu Desnoyers");
  73 MODULE_DESCRIPTION("Linux Trace Toolkit Test");
  74