Re: [PATCH 1/1, v6] cgroup/freezer: add per freezer duty ratio control

[Arjan van de Ven <arjan@linux.intel.com>]

On 2/9/2011 7:04 PM, Matt Helsley wrote:
> On Tue, Feb 08, 2011 at 05:05:41PM -0800, jacob.jun.pan@linux.intel.com wrote:
>> From: Jacob Pan<jacob.jun.pan@linux.intel.com>
>>
>> Freezer subsystem is used to manage batch jobs which can start
>> stop at the same time. However, sometime it is desirable to let
>> the kernel manage the freezer state automatically with a given
>> duty ratio.
>> For example, if we want to reduce the time that backgroup apps
>> are allowed to run we can put them into a freezer subsystem and
>> set the kernel to turn them THAWED/FROZEN at given duty ratio.
>>
>> This patch introduces two file nodes under cgroup
>> freezer.duty_ratio_pct and freezer.period_sec
>>
>> Usage example: set period to be 5 seconds and frozen duty ratio 90%
>> [root@localhost aoa]# echo 90>  freezer.duty_ratio_pct
>> [root@localhost aoa]# echo 5000>  freezer.period_ms
> I kept wondering how this was useful when we've got the "cpu" subsystem
> because for some reason "duty cycle" made me think this was a scheduling
> policy knob. In fact, I'm pretty sure it is -- it just happens to
> sometimes reduce power consumption.
>
> Have you tried using the cpu cgroup subsystem's share to see if it can
> have a similar effect?

does the cpu cgroup system work on a 20 to 30 second time window?
the objective is to have the CPU idle, without wakeups, for that long...
(to save power)