I'm not entirely sure what we can do about this; performance of the calls is likely to be driven by the speed of the underlying hardware supporting ceilometer and mongodb. This does not sound like a charm specific problem, so I'm going to push this to the Ubuntu package - it would be useful if you can provide details as to which version of OpenStack and Ubuntu where being used when you saw this issue.
I'm not entirely sure what we can do about this; performance of the calls is likely to be driven by the speed of the underlying hardware supporting ceilometer and mongodb. This does not sound like a charm specific problem, so I'm going to push this to the Ubuntu package - it would be useful if you can provide details as to which version of OpenStack and Ubuntu where being used when you saw this issue.