#include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/delay.h>
 #include <linux/sched.h>

 static void m_udelay(int us,struct timespec *start,
     struct timespec *end)
 {
     ktime_get_ts( start );
     udelay( us );
     ktime_get_ts( end );
 }

 static void m_udelay_ir(int us,struct timespec *start,
     struct timespec *end)
 {
     static spinlock_t mylock;

     spin_lock_irq( &mylock );
     ktime_get_ts( start );
     udelay( us );
     ktime_get_ts( end );
     spin_unlock_irq( &mylock );
 }

 static void m_usleep(int us,struct timespec *start,
     struct timespec *end)
 {
     ktime_get_ts( start );
     usleep_range( us, us );
     ktime_get_ts( end );
 }

 static void m_msleep(int ms,struct timespec *start,
     struct timespec *end)
 {
     ktime_get_ts( start );
     msleep( ms );
     ktime_get_ts( end );
 }

 static void loop( void (*messure)(int,struct timespec*,
     struct timespec*),int tm)
 {
     unsigned long i, diff, mean, shortest=0x7fffffff, highest=0;
     struct timespec start;
     struct timespec end;
     unsigned long before_us, after_us;
     for (i=0, mean=0; i<1000; i++) {
         messure( tm, &start, &end );
         before_us = (start.tv_sec*1000000)+(start.tv_nsec/1000);
         after_us = (end.tv_sec*1000000)+(end.tv_nsec/1000);
         diff = after_us - before_us;

         mean += diff;
         if (diff > highest)
             highest = diff;
         if (diff < shortest)
             shortest = diff;
     }
     mean = mean / i;
     printk("shortest: %ld mean: %ld highest: %ld\n",
         shortest, mean, highest);
     return;
 }

 static int __user mod_init( void )
 {
     struct sched_param schedpar;

     loop( m_udelay, 15 );
     loop( m_udelay_ir, 15 );
     loop( m_udelay_ir, 100 );
     loop( m_usleep, 15 );
     schedpar.sched_priority = 99;
     sched_setscheduler( current, SCHED_FIFO, &schedpar );
     loop( m_usleep, 15 );
     loop( m_usleep, 100 );
     sched_setscheduler( current, SCHED_NORMAL, &schedpar );
     loop( m_usleep, 110000 );
     loop( m_msleep, 10 );
     loop( m_msleep, 15 );
     loop( m_msleep, 18 );
     loop( m_msleep, 24 );
     loop( m_msleep, 50 );
     loop( m_msleep, 100 );
     loop( m_msleep, 110 );
     return -EIO;
 }

 static void __exit mod_exit( void )
 {
     return;
 }

 module_init( mod_init );
 module_exit( mod_exit );

 MODULE_LICENSE("GPL");