UMA Data Capture Interface (DCI)
Copyright © 1997 The Open Group
APIApplication Programming Interface. A standard interface
for program access to a set of services. The DCI API is
defined in this document.
Data Capture InterfaceThe API for the Data Capture Layer.
Data Capture LayerThe lowest layer in the UMA
It is concerned with the collection of raw data from the system.
DCIData Capture Interface
DCI serverAn abstraction provided by the DCI. The DCI
server provides a set of services to metrics providers and consumers.
DCLData Capture Layer
event, event metricAn event is a metric.
An occurrence of some activity of interest
to a metrics consumer (for example, thread
i18nabbreviation used in this specification for the term
(which has 18 letters between its first and last letters).
metricA single measurement. Metrics
have unique identifiers defined through
the metrics name space. A metric is either
a polled metric (indicating some statistic
or other data) or it is an event.
Polled metrics have metric values that can
be obtained by querying the DCI.
Events may have associated data returned with
the event when it occurs. (See
Events and Event Data Attributes
metric classMetrics are grouped into metric classes.
Classes are organised in a hierarchy.
A metric class holds no metric values. It
is simply a placeholder in the namespace.
It should be viewed as a template.
metric class instanceMetric values are associated with
instantiations of metric classes. For
example, there could be a class for
per-thread statistics; associated with
this class could be many instances, each
one identified by its thread id. A
particular thread's statistics would
be available by querying the DCI for
that specific metric class instance.
metrics consumerAny application which needs to import metrics.
metrics providerAny subsystem which has metrics to export. The
subsystem can either be the operating system or applications.
metric valueThe value of a polled metric is referred
to as a metric value. Note that metrics
that are events do not have metric values.
MLIThe Measurement Layer Interface. An upper level service, one of the
possible DCI consumers, that provides a measurement control and data
multiprocessor systemAny machine which contains more than one processor but appears to the
user to be running a single operating system.
octetAn eight bit unit of storage.
operating systemPrivileged software which controls hardware resources.
PMWGPerformance Management Working Group. The group which has
specified the Universal Measurement Architecture.
polled metricA polled metric is a metric. It
typically corresponds to a numerical
count of some system activity, some
statistic, or possibly some configuration
information (for example, the number of processors).
securityThat part of an operating system concerned with controlling
access to information.
system spaceAn address space in which privileged programs, such as
the operating system, are run.
user spaceAn address space in which unprivileged programs are run. Examples of
such programs are applications or system services which do not require
direct access to hardware resources.
UMAUniversal Measurement Architecture. The collection of the DCI,
Data Pool and MLI that provides a complete performance
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