tests/kernel/test-spinlock.c

   1 /* test-cmpxchg.c
   2  *
   3  * Test time spent in a LTTng instrumentation probe.
   4  */
   5
   6
   7 #include <linux/config.h>
   8 #include <linux/jiffies.h>
   9 #include <linux/compiler.h>
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/spinlock.h>
  13
  14 #define NR_LOOPS 20000
  15
  16 volatile int test_val = 100;
  17
  18 spinlock_t lock = SPIN_LOCK_UNLOCKED;
  19
  20 static inline void do_test(void)
  21 {
  22         unsigned long flags;
  23
  24         spin_lock_irqsave(&lock, flags);
  25         test_val += 1;
  26         spin_unlock_irqrestore(&lock, flags);
  27 }
  28
  29 //void (*fct)(void) = do_test;
  30
  31 static int ltt_test_init(void)
  32 {
  33         unsigned int i;
  34         cycles_t time1, time2, time;
  35         cycles_t max_time = 0, min_time = 18446744073709551615ULL; /* (2^64)-1 */
  36         cycles_t tot_time = 0;
  37         unsigned long flags;
  38         printk(KERN_ALERT "test init\n");
  39
  40         local_irq_save(flags);
  41         time1 = get_cycles();
  42         for(i=0; i<NR_LOOPS; i++) {
  43                 //for(int j=0; j<10; j++) {
  44                 do_test();
  45                 //}
  46                 //max_time = max(max_time, time);
  47                 //min_time = min(min_time, time);
  48                 //printk("val : %d\n", test_val);
  49         }
  50         time2 = get_cycles();
  51         local_irq_restore(flags);
  52         time = time2 - time1;
  53         tot_time += time;
  54
  55         printk(KERN_ALERT "test results : time for spinlock irqsave\n");
  56         printk(KERN_ALERT "number of loops : %d\n", NR_LOOPS);
  57         printk(KERN_ALERT "total time : %llu\n", tot_time);
  58         //printk(KERN_ALERT "min : %llu\n", min_time);
  59         //printk(KERN_ALERT "max : %llu\n", max_time);
  60
  61         printk(KERN_ALERT "test end\n");
  62
  63         return -EAGAIN; /* Fail will directly unload the module */
  64 }
  65
  66 static void ltt_test_exit(void)
  67 {
  68         printk(KERN_ALERT "test exit\n");
  69 }
  70
  71 module_init(ltt_test_init)
  72 module_exit(ltt_test_exit)
  73
  74 MODULE_LICENSE("GPL");
  75 MODULE_AUTHOR("Mathieu Desnoyers");
  76 MODULE_DESCRIPTION("Linux Trace Toolkit Test");
  77