openstack team mailing list archive

[Eoghan Glynn <eglynn@xxxxxxxxxx>]

> > I don't think (max - min) would suffice to give an accurate
> > measure of the actual CPU time used, as the counter may have
> > reset multiple times in the course of the requested duration.
> 
> It is, because /max in the API should be aware of the fact a 
> reset can occur and computes accordingly. We started to discuss
> this a bit in:
> 
>       https://bugs.launchpad.net/ceilometer/+bug/1061817

A-ha, OK, so not so much (max - min) as:

   (\Sigma local maxima) - first

Sounds computationally expensive to produce on the fly, but maybe
the local maxima can be efficiently recorded as the data is being
ingested.

Cheers,
Eoghan