update rwlock

git-svn-id: http://ltt.polymtl.ca/svn@3391 04897980-b3bd-0310-b5e0-8ef037075253

diff --git a/trunk/tests/kernel/test-read-lock-speed.c b/trunk/tests/kernel/test-read-lock-speed.c
index 31e40f10fcf71a9fea18af76f9365ce65da0cdb9..979f1bc8cba91575a8b3dc0d856598d5cbe86d04 100644 (file)
--- a/trunk/tests/kernel/test-read-lock-speed.c
+++ b/trunk/tests/kernel/test-read-lock-speed.c
@@ -2,8 +2,8 @@
  * test-read-lock-speed.c
  *
  * Compare speed of :
- * - spin lock irqsave / spin unlock irqrestore (close to rwlocks when
- *   uncontended)
+ * - spin lock irqsave / spin unlock irqrestore (protects from interrupts)
+ * - rwlock read lock (not disabling interrupts, can deal with nesting)
  * - using a sequence read lock (uncontended)
  * - preempt disable/enable (RCU)
  *
@@ -96,6 +96,36 @@ static void do_test_spinlock(void)
        printk(KERN_ALERT "test end\n");
 }
 
+static void do_test_read_rwlock(void)
+{
+       static DEFINE_RWLOCK(mylock);
+       unsigned long flags;
+       unsigned int i;
+       cycles_t time1, time2, time;
+       u32 rem;
+
+       preempt_disable();
+       local_irq_save(flags);
+       read_lock(&mylock);
+       time1 = get_cycles();
+       for (i = 0; i < NR_LOOPS; i++) {
+               read_unlock(&mylock);
+               read_lock(&mylock);
+       }
+       time2 = get_cycles();
+       read_unlock(&mylock);
+       local_irq_restore(flags);
+       preempt_enable();
+       time = time2 - time1;
+
+       printk(KERN_ALERT "test results: time for read rwlock\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 "-> read rwlock takes %llu cycles\n", time);
+       printk(KERN_ALERT "test end\n");
+}
+
 static void do_test_seqlock(void)
 {
        static seqlock_t test_lock;
@@ -166,6 +196,7 @@ static int ltt_test_init(void)
        printk(KERN_ALERT "Number of active CPUs : %d\n", num_online_cpus());
        do_testbaseline();
        do_test_spinlock();
+       do_test_read_rwlock();
        do_test_seqlock();
        do_test_preempt();
        return -EAGAIN; /* Fail will directly unload the module */