Add arm-armada-xp-update_cpuidle

1 files changed, 67 insertions, 0 deletions

diff --git a/arm-armada-xp-update_cpuidle.patch b/arm-armada-xp-update_cpuidle.patch
new file mode 100644
index 00000000..04783656
--- /dev/null
+++ b/arm-armada-xp-update_cpuidle.patch
@@ -0,0 +1,67 @@
+Date: Fri, 13 Feb 2015 15:55:03 +0100 (CET)
+From: "s. rannou" <mxs@sbrk.org>
+To: Jason Cooper <jason@lakedaemon.net>
+Subject: [PATCH] cpuidle: mvebu: update cpuidle thresholds for Armada XP SOCs
+
+Originally, the thresholds used in the cpuidle driver for Armada SOCs
+were temporarily chosen, leaving room for improvements.
+
+This commit updates the thresholds for the Armada XP SOCs with values
+that positively impact performances:
+
+                                without patch  with patch   vendor kernel
+ - iperf localhost (gbit/sec)   ~3.7           ~6.4         ~5.4
+ - ioping tmpfs (iops)          ~163k          ~206k        ~179k
+ - ioping tmpfs (mib/s)         ~636           ~805         ~699
+
+The idle power consumption is negatively impacted (proportionally less
+than the performance gain), and we are still performing better than
+the vendor kernel here:
+
+                                without patch   with patch  vendor kernel
+ - power consumption idle (W)   ~2.4            ~3.2        ~4.4
+ - power consumption busy (W)   ~8.6            ~8.3        ~8.6
+
+There is still room for improvement regarding the value of these
+thresholds, they were chosen to mimic the vendor kernel.
+
+This patch only impacts Armada XP SOCs and was tested on Online Labs
+C1 boards. A similar approach can be taken to improve the performances
+of the Armada 370 and Armada 38x SOCs.
+
+Thanks a lot to Thomas Petazzoni, Gregory Clement and Willy Tarreau
+for the discussions and tips around this topic.
+
+Signed-off-by: Sebastien Rannou <mxs@sbrk.org>
+---
+ drivers/cpuidle/cpuidle-mvebu-v7.c | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/drivers/cpuidle/cpuidle-mvebu-v7.c b/drivers/cpuidle/cpuidle-mvebu-v7.c
+index 38e6861..3716a1f 100644
+--- a/drivers/cpuidle/cpuidle-mvebu-v7.c
++++ b/drivers/cpuidle/cpuidle-mvebu-v7.c
+@@ -50,17 +50,17 @@ static struct cpuidle_driver armadaxp_idle_driver = {
+ 	.states[0]		= ARM_CPUIDLE_WFI_STATE,
+ 	.states[1]		= {
+ 		.enter			= mvebu_v7_enter_idle,
+-		.exit_latency		= 10,
++		.exit_latency		= 100,
+ 		.power_usage		= 50,
+-		.target_residency	= 100,
++		.target_residency	= 1000,
+ 		.name			= "MV CPU IDLE",
+ 		.desc			= "CPU power down",
+ 	},
+ 	.states[2]		= {
+ 		.enter			= mvebu_v7_enter_idle,
+-		.exit_latency		= 100,
++		.exit_latency		= 1000,
+ 		.power_usage		= 5,
+-		.target_residency	= 1000,
++		.target_residency	= 10000,
+ 		.flags			= MVEBU_V7_FLAG_DEEP_IDLE,
+ 		.name			= "MV CPU DEEP IDLE",
+ 		.desc			= "CPU and L2 Fabric power down",
+-- 
+2.1.4