[PATCH] cpuidle: mvebu: update cpuidle thresholds for Armada XP SOCs
From: Gregory CLEMENT <hidden>
Date: 2015-02-24 17:36:03
Also in:
linux-pm
Hi Sebastien, On 13/02/2015 15:55, s. rannou wrote:
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.Thanks for your work and all the test you have done. As you mentioned there should be still room for improvement, but this patch is already a step in the good direction. So you can add my: Acked-by: Gregory CLEMENT <redacted> While this driver is related to mvebu SoCs, it is not part of the mvebu subsystem but of the PM subsystem and should be taken by its maintainers. I added them in copy as well as the pm list. Daniel and Rafael, if you didn't get the original email I can bounced if needed. I also wonder it it would worth applying it on the stable branch. What do you think about it? Thanks, Gregory
quoted hunk ↗ jump to hunk
Signed-off-by: Sebastien Rannou <redacted> --- 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",
-- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com