From 6a328475cccacb99a13b06978091da936dd51d89 Mon Sep 17 00:00:00 2001
From: Jim Kukunas <james.t.kukunas@linux.intel.com>
Date: Tue, 22 May 2012 13:54:03 +1000
Subject: [PATCH] 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>
---
crypto/xor.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/crypto/xor.c b/crypto/xor.c
index b75182d8ab146..87884435bddb1 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();
--
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