precision of floating point metering stats is discarded unnecessarily

[Eoghan Glynn]

Ceilometer returns aggregated statistical values as float, whereas the 'resource usage' panel narrows to int before inserting these data into the line chart.

For meters defined over a narrow range (such as cpu_util ranging from 0.0% to 100.0%) this has the effect of unnaturally smoothening the graph by discarding precision.

If it really was crucial that the line chart contain only ints, then the float->int conversion should be a round:

  i = int(round(f, 0))

as opposed to narrowing cast:

  i = int(f)

However, AFAICS there's no reason why these raw data couldn't be represented directly as floats in the line chart.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/52603

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/52603
Committed: http://github.com/openstack/horizon/commit/4b973c2fb49b3a1a0d38c3788f45b3af076625d0
Submitter: Jenkins
Branch: master

commit 4b973c2fb49b3a1a0d38c3788f45b3af076625d0
Author: Eoghan Glynn <email address hidden>
Date: Fri Oct 18 10:53:44 2013 +0100

    Avoid discarding precision of metering data

    Fixes bug 1241467

    Narrow-casting statistical aggregates to int before inserting
    into the resource usage line charts had the effect of unnaturally
    smoothening the trend. This was especially apparent for meters
    defined over a narrow range (such as cpu_util ranging from 0.0%
    to 100.0%).

    We now maintain floating point precision for these data.

    Change-Id: If6141a4f66aa0078d38aa9f53d913aca5684ad94

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/havana
Review: https://review.openstack.org/52868

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/52868
Committed: http://github.com/openstack/horizon/commit/d97bba1d0736cbf1c5a28d948854141b740111bb
Submitter: Jenkins
Branch: stable/havana

commit d97bba1d0736cbf1c5a28d948854141b740111bb
Author: Eoghan Glynn <email address hidden>
Date: Fri Oct 18 10:53:44 2013 +0100

    Avoid discarding precision of metering data

    Fixes bug 1241467

    Narrow-casting statistical aggregates to int before inserting
    into the resource usage line charts had the effect of unnaturally
    smoothening the trend. This was especially apparent for meters
    defined over a narrow range (such as cpu_util ranging from 0.0%
    to 100.0%).

    We now maintain floating point precision for these data.

    Change-Id: If6141a4f66aa0078d38aa9f53d913aca5684ad94
    (cherry picked from commit 4b973c2fb49b3a1a0d38c3788f45b3af076625d0)