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authorJim Kukunas <james.t.kukunas@linux.intel.com>2012-05-22 13:54:03 +1000
committerNeilBrown <neilb@suse.de>2012-05-22 13:54:03 +1000
commit6a328475cccacb99a13b06978091da936dd51d89 (patch)
treef4fc193b5ec71f7c7dfc0a33341d80a2c103c205 /crypto/xor.c
parent3ea7daa5d7fde47cd41f4d56c2deb949114da9d6 (diff)
downloadlinux-6a328475cccacb99a13b06978091da936dd51d89.tar.gz
crypto: wait for a full jiffy in do_xor_speed
In the existing do_xor_speed(), there is no guarantee that we actually
run do_2() for a full jiffy. We get the current jiffy, then run do_2()
until the next jiffy.

Instead, let's get the current jiffy, then wait until the next jiffy
to start our test.

Signed-off-by: Jim Kukunas <james.t.kukunas@linux.intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'crypto/xor.c')
-rw-r--r--crypto/xor.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/crypto/xor.c b/crypto/xor.c
index b75182d8ab14..87884435bddb 100644
--- a/crypto/xor.c
+++ b/crypto/xor.c
@@ -63,7 +63,7 @@ static void
 do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
 {
 	int speed;
-	unsigned long now;
+	unsigned long now, j;
 	int i, count, max;
 
 	tmpl->next = template_list;
@@ -76,9 +76,11 @@ do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
 	 */
 	max = 0;
 	for (i = 0; i < 5; i++) {
-		now = jiffies;
+		j = jiffies;
 		count = 0;
-		while (jiffies == now) {
+		while ((now = jiffies) == j)
+			cpu_relax();
+		while (time_before(jiffies, now + 1)) {
 			mb(); /* prevent loop optimzation */
 			tmpl->do_2(BENCH_SIZE, b1, b2);
 			mb();