+static void do_testbaseline(void)
+{
+ unsigned long flags;
+ unsigned int i;
+ cycles_t time1, time2, time;
+ u32 rem;
+
+ local_irq_save(flags);
+ preempt_disable();
+ time1 = get_cycles();
+ for (i = 0; i < NR_LOOPS; i++) {
+ asm volatile ("");
+ }
+ time2 = get_cycles();
+ local_irq_restore(flags);
+ preempt_enable();
+ time = time2 - time1;
+
+ printk(KERN_ALERT "test results: time for baseline\n");
+ printk(KERN_ALERT "number of loops: %d\n", NR_LOOPS);
+ printk(KERN_ALERT "total time: %llu\n", time);
+ time = div_u64_rem(time, NR_LOOPS, &rem);
+ printk(KERN_ALERT "-> baseline takes %llu cycles\n", time);
+ printk(KERN_ALERT "test end\n");
+}
+
+static void do_test_sync_cmpxchg(void)
+{
+ int ret;
+ unsigned long flags;
+ unsigned int i;
+ cycles_t time1, time2, time;
+ u32 rem;
+
+ local_irq_save(flags);
+ preempt_disable();
+ time1 = get_cycles();
+ for (i = 0; i < NR_LOOPS; i++) {
+#ifdef CONFIG_X86_32
+ ret = sync_cmpxchg(&test_val, 0, 0);
+#else
+ ret = cmpxchg(&test_val, 0, 0);
+#endif
+ }
+ time2 = get_cycles();
+ local_irq_restore(flags);
+ preempt_enable();
+ time = time2 - time1;
+
+ printk(KERN_ALERT "test results: time for locked cmpxchg\n");
+ printk(KERN_ALERT "number of loops: %d\n", NR_LOOPS);
+ printk(KERN_ALERT "total time: %llu\n", time);
+ time = div_u64_rem(time, NR_LOOPS, &rem);
+ printk(KERN_ALERT "-> locked cmpxchg takes %llu cycles\n", time);
+ printk(KERN_ALERT "test end\n");
+}
+