Idle time statistics for a container

Hi Kirill/Hertbert,
Does Openvz or Linux-VServer provide idle time statistics per
container? i.e how much time a container has been idle?

Just exploring whether that be a usefull stats to provide on a per-control group basis.

Regards,
vatsa

yes, OpenVZ calculates idle statistics for VE.
it is calculated as follows:
cpu user/system time are incremented as usual on timer tick, idle time is incremented on per-VE per-VCPU runqueue when there is no tasks in VE runqueue.

i.e. VE idle time is the time when there were no VE tasks on the runqueue.

Linux-VServer accounts the time/ticks a contain was running and on hold for being over limits, the time running is broken down into sys/user/etc ...

so, while it is not accounted per se, it can be easily calculated from the other vaules ...

I think it makes perfectly sense to account that, and a smart version is required to get the statistics inside a container right :)

best,
Herbert

With the group cfs scheduler, it may be bit easy to provide this. If I am not mistaken, se->sum_sleep_runtime would provide this idle time, where 'se' is the group level schedulable entity representing a container/control-group on a cpu.

Regards,
vatsa