Config knob to disable collecting root cgroup stats

[sashankreddya]

We have seen a performance issue while reading memory.stat file for “rootCgroup”. It might be partially due to a kernel issue . The time taken to read "/sys/fs/cgroup/memory/memory.stat" is of the order of "3~8s". This also correlates to one of the earlier discussion thread as in here seen by others of the openSource community. Once we disable collecting root cgroup stats with some thing like below, the CPU spike reduced from close to 100% to 2%.

func (self *rawContainerHandler) GetStats() (*info.ContainerStats, error) { if disable_rootCgroup_stats && isRootCgroup(self.name) { return nil, nil }

It would be nice if we can have a config knob to not collect root cgroup stats if set.