On Tue, Nov 06, 2012 at 09:09:57PM +0800, Alex Shi wrote:
> This patch add the power aware scheduler knob into sysfs:
>
> $cat /sys/devices/system/cpu/sched_policy/available_sched_policy
> performance powersaving
>
> $cat /sys/devices/system/cpu/sched_policy/current_sched_policy
> powersaving
>
> The using sched policy is 'powersaving'. User can change the policy
> by commend 'echo':
> echo performance > /sys/devices/system/cpu/current_sched_policy
>
> Power aware scheduling will has different behavior according to
> different policy:
>
> performance: the current scheduling behaviour, try to spread tasks
> on more CPU sockets or cores.
> powersaving: will shrink tasks into sched group until the group's
> nr_running is up to group_weight.
>
> Signed-off-by: Alex Shi <alex....@intel.com>
> ---
> Documentation/ABI/testing/sysfs-devices-system-cpu | 21 +++++++
> drivers/base/cpu.c | 2 +
> include/linux/cpu.h | 2 +
> kernel/sched/fair.c | 68
> +++++++++++++++++++++-
> kernel/sched/sched.h | 5 ++
> 5 files changed, 97 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu
> b/Documentation/ABI/testing/sysfs-devices-system-cpu
> index 6943133..1909d3e 100644
> --- a/Documentation/ABI/testing/sysfs-devices-system-cpu
> +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
> @@ -53,6 +53,27 @@ 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_policy/current_sched_policy
> + /sys/devices/system/cpu/sched_policy/available_sched_policy
> +Date: Oct 2012
> +Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
> +Description: CFS scheduler policy showing and setting interface.
> +
> + available_sched_policy shows there are 2 kinds of policy now:
> + performance and powersaving.
> + current_sched_policy shows current scheduler policy. And user
> + can change the policy by writing it.
> +
> + Policy decides that CFS scheduler how to distribute tasks onto
> + which CPU unit when tasks number less than LCPU number in system
> +
> + performance: try to spread tasks onto more CPU sockets,
> + more CPU cores.
> +
> + powersaving: try to shrink tasks onto same core or same CPU
> + until running task number beyond the LCPU number in the core
> + or socket.
> +
> What: /sys/devices/system/cpu/cpu#/node
> Date: October 2009
> Contact: Linux memory management mailing list <linux...@kvack.org>
> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> index 6345294..5f6a573 100644
> --- a/drivers/base/cpu.c
> +++ b/drivers/base/cpu.c
> @@ -330,4 +330,6 @@ void __init cpu_dev_init(void)
> panic("Failed to register CPU subsystem");
>
> cpu_dev_register_generic();
> +
> + create_sysfs_sched_policy_group(cpu_subsys.dev_root);
Are you sure you didn't just race with userspace, creating the sysfs
files after the device was created and announced to userspace?
If so, you need to fix this :)
thanks,
greg k-h
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