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authorJean Delvare <jdelvare@suse.de>2016-01-11 17:41:53 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-01-15 22:36:19 +0100
commit66a5f6b63996d8aa7cbe8841b38297bf3b338194 (patch)
tree2ac1b2bc7f7eb482ca2a5b12982f45e275e3de16
parenttime: nohz: Expose tick_nohz_enabled (diff)
downloadlinux-66a5f6b63996d8aa7cbe8841b38297bf3b338194.tar.xz
linux-66a5f6b63996d8aa7cbe8841b38297bf3b338194.zip
cpuidle: Default to ladder governor on ticking systems
The menu governor is currently the default on all systems. However the documentation claims that the ladder governor is preferred on ticking systems. So bump the rating of the ladder governor when NO_HZ is disabled, or when booting with nohz=off. This fixes the first half of kernel BZ #65531. Link: https://bugzilla.kernel.org/show_bug.cgi?id=65531 Signed-off-by: Jean Delvare <jdelvare@suse.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--drivers/cpuidle/governors/ladder.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
index 401c0106ed34..63bd5a403e22 100644
--- a/drivers/cpuidle/governors/ladder.c
+++ b/drivers/cpuidle/governors/ladder.c
@@ -17,6 +17,7 @@
#include <linux/pm_qos.h>
#include <linux/module.h>
#include <linux/jiffies.h>
+#include <linux/tick.h>
#include <asm/io.h>
#include <asm/uaccess.h>
@@ -184,6 +185,14 @@ static struct cpuidle_governor ladder_governor = {
*/
static int __init init_ladder(void)
{
+ /*
+ * When NO_HZ is disabled, or when booting with nohz=off, the ladder
+ * governor is better so give it a higher rating than the menu
+ * governor.
+ */
+ if (!tick_nohz_enabled)
+ ladder_governor.rating = 25;
+
return cpuidle_register_governor(&ladder_governor);
}