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authorRamesh Thomas <ramesh.thomas@intel.com>2017-10-26 19:01:34 -0700
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-11-08 12:16:01 +0100
commitc523c68da2117a3f9f777110839b1cf7ed7221be (patch)
tree2b06b4593e6af9d9614fc8a4c4c1d41f88eb1144 /drivers/cpuidle
parent4e37fd4d5dfd39f547b0b00fa184a440a1e44b96 (diff)
cpuidle: ladder: Add per CPU PM QoS resume latency support
Individual CPUs may have special requirements to not enter deep idle states. For example, a CPU running real time applications would not want to enter deep idle states to avoid latency impacts. At the same time other CPUs that do not have such a requirement could allow deep idle states to save power. This was already implemented in the menu governor. Implementing similar changes in the ladder governor which gets selected when CONFIG_NO_HZ and CONFIG_NO_HZ_IDLE are not set. Refer following commits for the menu governor changes. Signed-off-by: Ramesh Thomas <ramesh.thomas@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/governors/ladder.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
index ce1a2ffffb2a..1ad8745fd6d6 100644
--- a/drivers/cpuidle/governors/ladder.c
+++ b/drivers/cpuidle/governors/ladder.c
@@ -17,6 +17,7 @@
#include <linux/pm_qos.h>
#include <linux/jiffies.h>
#include <linux/tick.h>
+#include <linux/cpu.h>
#include <asm/io.h>
#include <linux/uaccess.h>
@@ -67,10 +68,16 @@ static int ladder_select_state(struct cpuidle_driver *drv,
struct cpuidle_device *dev)
{
struct ladder_device *ldev = this_cpu_ptr(&ladder_devices);
+ struct device *device = get_cpu_device(dev->cpu);
struct ladder_device_state *last_state;
int last_residency, last_idx = ldev->last_state_idx;
int first_idx = drv->states[0].flags & CPUIDLE_FLAG_POLLING ? 1 : 0;
int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
+ int resume_latency = dev_pm_qos_raw_read_value(device);
+
+ if (resume_latency < latency_req &&
+ resume_latency != PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)
+ latency_req = resume_latency;
/* Special case when user has set very strict latency requirement */
if (unlikely(latency_req == 0)) {