Reference Guide

 An instantaneous measure.
 Example application: the amount of disk space consumed by metric data.
•
TimeStampedHistogram
 A distribution of values from a stream of data for which mean, minimum, maximum, and
various quartile values are tracked.
 Example application: distribution of OpenFlow flow sizes.
•
TimeStampedMeter
 Aggregates event durations to measure event throughput.
 Example application: the frequency with which OpenFlow flow requests are sent to the
controller by a specific switch.
•
TimeStampedRatioGauge
 A ratio between two non-cumulative instantaneous numbers.
 Example application: the amount of disk space consumed by a specific application's
metric data compared to all metric data.
•
TimeStampedRollingCounter
 A cumulative measurement that is asymptotically increased when some event occurs, and
may eventually roll over to zero and begin anew.
 Example application: a MIB counter that represents the number of octets observed in a
specific subnet.
•
TimeStampedTimer (combines the functionality of TimeStampedHistogram and
TimeStampedMeter)
 Aggregates event durations to provide statistics about the event duration and throughput.
 Example application: the rate at which entries are placed on a queue and a histogram
of the time they spent on the queue.
TimeStampedMetric Life Cycle
Creating a TimeStampedMetric
It is possible to create a TimeStampedMetric and track its value from a component or application
that is running within the controller.
To request that the MetricService create a new TimeStampedMetric, a component or application
must provide a MetricDescriptor object that specifies the characteristics of the desired
TimeStampedMetric. A MetricDescriptor contains four fields that, when combined, produce a
combination (four-tuple) that is unique to that MetricDescriptor and the resulting
TimeStampedMetric: an application ID, a primary tag, a secondary tag, and a metric name. The
MetricDescriptor also contains other fields, as follows.
Required Field(s)
•
A name that is unique among TimeStampedMetrics of the same application ID, primary tag,
and secondary tag combination (String).
Optional Field(s)
•
The ID of the application creating the TimeStampedMetric instance (String, defaulted to the
application ID).
48