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linux-next/drivers/cpuidle/cpuidle-mvebu-v7.c
Sebastien Rannou ce6031c89a 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>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
2015-03-13 18:31:29 +01:00

144 lines
3.5 KiB
C

/*
* Marvell Armada 370, 38x and XP SoC cpuidle driver
*
* Copyright (C) 2014 Marvell
*
* Nadav Haklai <nadavh@marvell.com>
* Gregory CLEMENT <gregory.clement@free-electrons.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*
* Maintainer: Gregory CLEMENT <gregory.clement@free-electrons.com>
*/
#include <linux/cpu_pm.h>
#include <linux/cpuidle.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/suspend.h>
#include <linux/platform_device.h>
#include <asm/cpuidle.h>
#define MVEBU_V7_FLAG_DEEP_IDLE 0x10000
static int (*mvebu_v7_cpu_suspend)(int);
static int mvebu_v7_enter_idle(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
int ret;
bool deepidle = false;
cpu_pm_enter();
if (drv->states[index].flags & MVEBU_V7_FLAG_DEEP_IDLE)
deepidle = true;
ret = mvebu_v7_cpu_suspend(deepidle);
cpu_pm_exit();
if (ret)
return ret;
return index;
}
static struct cpuidle_driver armadaxp_idle_driver = {
.name = "armada_xp_idle",
.states[0] = ARM_CPUIDLE_WFI_STATE,
.states[1] = {
.enter = mvebu_v7_enter_idle,
.exit_latency = 100,
.power_usage = 50,
.target_residency = 1000,
.name = "MV CPU IDLE",
.desc = "CPU power down",
},
.states[2] = {
.enter = mvebu_v7_enter_idle,
.exit_latency = 1000,
.power_usage = 5,
.target_residency = 10000,
.flags = MVEBU_V7_FLAG_DEEP_IDLE,
.name = "MV CPU DEEP IDLE",
.desc = "CPU and L2 Fabric power down",
},
.state_count = 3,
};
static struct cpuidle_driver armada370_idle_driver = {
.name = "armada_370_idle",
.states[0] = ARM_CPUIDLE_WFI_STATE,
.states[1] = {
.enter = mvebu_v7_enter_idle,
.exit_latency = 100,
.power_usage = 5,
.target_residency = 1000,
.flags = MVEBU_V7_FLAG_DEEP_IDLE,
.name = "Deep Idle",
.desc = "CPU and L2 Fabric power down",
},
.state_count = 2,
};
static struct cpuidle_driver armada38x_idle_driver = {
.name = "armada_38x_idle",
.states[0] = ARM_CPUIDLE_WFI_STATE,
.states[1] = {
.enter = mvebu_v7_enter_idle,
.exit_latency = 10,
.power_usage = 5,
.target_residency = 100,
.name = "Idle",
.desc = "CPU and SCU power down",
},
.state_count = 2,
};
static int mvebu_v7_cpuidle_probe(struct platform_device *pdev)
{
mvebu_v7_cpu_suspend = pdev->dev.platform_data;
if (!strcmp(pdev->dev.driver->name, "cpuidle-armada-xp"))
return cpuidle_register(&armadaxp_idle_driver, NULL);
else if (!strcmp(pdev->dev.driver->name, "cpuidle-armada-370"))
return cpuidle_register(&armada370_idle_driver, NULL);
else if (!strcmp(pdev->dev.driver->name, "cpuidle-armada-38x"))
return cpuidle_register(&armada38x_idle_driver, NULL);
else
return -EINVAL;
}
static struct platform_driver armadaxp_cpuidle_plat_driver = {
.driver = {
.name = "cpuidle-armada-xp",
},
.probe = mvebu_v7_cpuidle_probe,
};
module_platform_driver(armadaxp_cpuidle_plat_driver);
static struct platform_driver armada370_cpuidle_plat_driver = {
.driver = {
.name = "cpuidle-armada-370",
},
.probe = mvebu_v7_cpuidle_probe,
};
module_platform_driver(armada370_cpuidle_plat_driver);
static struct platform_driver armada38x_cpuidle_plat_driver = {
.driver = {
.name = "cpuidle-armada-38x",
},
.probe = mvebu_v7_cpuidle_probe,
};
module_platform_driver(armada38x_cpuidle_plat_driver);
MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
MODULE_DESCRIPTION("Marvell EBU v7 cpuidle driver");
MODULE_LICENSE("GPL");