From: Alex Shi alex.shi@intel.com
This patch add the power aware scheduler knob into sysfs:
$cat /sys/devices/system/cpu/sched_balance_policy/available_sched_balance_policy performance powersaving $cat /sys/devices/system/cpu/sched_balance_policy/current_sched_balance_policy powersaving
This means the using sched balance policy is 'powersaving'.
User can change the policy by commend 'echo': echo performance > /sys/devices/system/cpu/sched_balance_policy/current_sched_balance_policy
Signed-off-by: Alex Shi alex.shi@intel.com [Added CONFIG_SCHED_POWER switch to enable this patch] Signed-off-by: Preeti U Murthy preeti@linux.vnet.ibm.com ---
Documentation/ABI/testing/sysfs-devices-system-cpu | 23 +++++++ kernel/sched/fair.c | 69 ++++++++++++++++++++ 2 files changed, 92 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index acb9bfc..c7ed5c1 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -53,6 +53,29 @@ Description: Dynamic addition and removal of CPU's. This is not hotplug the system. Information writtento the file to remove CPU's is architecture specific.
+What: /sys/devices/system/cpu/sched_balance_policy/current_sched_balance_policy + /sys/devices/system/cpu/sched_balance_policy/available_sched_balance_policy +Date: Oct 2012 +Contact: Linux kernel mailing list linux-kernel@vger.kernel.org +Description: CFS balance policy show and set interface. + This will get activated only when CONFIG_SCHED_POWER is set. + + available_sched_balance_policy: shows there are 2 kinds of + policies: + performance powersaving. + current_sched_balance_policy: shows current scheduler policy. + User can change the policy by writing it. + + Policy decides the CFS scheduler how to balance tasks onto + different CPU unit. + + performance: try to spread tasks onto more CPU sockets, + more CPU cores. performance oriented. + + powersaving: try to pack tasks onto same core or same CPU + until every LCPUs are busy in the core or CPU socket. + powersaving oriented. + What: /sys/devices/system/cpu/cpu#/node Date: October 2009 Contact: Linux memory management mailing list linux-mm@kvack.org diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 77da534..f1b0a33 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5863,6 +5863,75 @@ static inline int sg_imbalanced(struct sched_group *group) return group->sgc->imbalance; }
+#if defined(CONFIG_SYSFS) && defined(CONFIG_SCHED_POWER) +static ssize_t show_available_sched_balance_policy(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "performance powersaving\n"); +} + +static ssize_t show_current_sched_balance_policy(struct device *dev, + struct device_attribute *attr, char *buf) +{ + if (sched_balance_policy == SCHED_POLICY_PERFORMANCE) + return sprintf(buf, "performance\n"); + else if (sched_balance_policy == SCHED_POLICY_POWERSAVING) + return sprintf(buf, "powersaving\n"); + return 0; +} + +static ssize_t set_sched_balance_policy(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + unsigned int ret = -EINVAL; + char str_policy[16]; + + ret = sscanf(buf, "%15s", str_policy); + if (ret != 1) + return -EINVAL; + + if (!strcmp(str_policy, "performance")) + sched_balance_policy = SCHED_POLICY_PERFORMANCE; + else if (!strcmp(str_policy, "powersaving")) + sched_balance_policy = SCHED_POLICY_POWERSAVING; + else + return -EINVAL; + + return count; +} + +/* + * * Sysfs setup bits: + * */ +static DEVICE_ATTR(current_sched_balance_policy, 0644, + show_current_sched_balance_policy, set_sched_balance_policy); + +static DEVICE_ATTR(available_sched_balance_policy, 0444, + show_available_sched_balance_policy, NULL); + +static struct attribute *sched_balance_policy_default_attrs[] = { + &dev_attr_current_sched_balance_policy.attr, + &dev_attr_available_sched_balance_policy.attr, + NULL +}; +static struct attribute_group sched_balance_policy_attr_group = { + .attrs = sched_balance_policy_default_attrs, + .name = "sched_balance_policy", +}; + +int __init create_sysfs_sched_balance_policy_group(struct device *dev) +{ + return sysfs_create_group(&dev->kobj, &sched_balance_policy_attr_group); +} + +static int __init sched_balance_policy_sysfs_init(void) +{ + return create_sysfs_sched_balance_policy_group(cpu_subsys.dev_root); +} + +core_initcall(sched_balance_policy_sysfs_init); +#endif /* CONFIG_SYSFS && CONFIG_SCHED_POWER*/ + /* * Compute the group capacity factor. *