Comment 5 for bug 1417949

Reviewed: https://review.openstack.org/221907
Committed: https://git.openstack.org/cgit/openstack/ceilometer/commit/?id=6ef079953e343885fb6251bc7bbb3c13b8e89483
Submitter: Jenkins
Branch: master

commit 6ef079953e343885fb6251bc7bbb3c13b8e89483
Author: gordon chung <email address hidden>
Date: Wed Sep 9 14:28:34 2015 -0400

    add delta transfomer support

    this patch adds support for a delta transformer. the transformer's
    only functionality is to calculate the delta between current sample
    and previous sample.

    conditions:
    - it will disregard any out of order samples
    - a growth_only param is available to capture only positive deltas
    - supports renaming to a new meter name using same schema as other
      transformers.

    using this transformer, we also create a cpu.delta meter which will
    enable another view of cpu meter. this delta meter will allow for
    (relatively) accurate cputime calculations and will cope with cputime
    resets.

    DocImpact

    Change-Id: Iabcad20d500e3157e4d19f8b2ebffd770218165b
    Closes-Bug: #1417949