When using the Performance Metrics Programming Interface (PMAPI) of
the Performance Co-Pilot (PCP), performance metrics are identified by
an external name in a hierarchic Performance Metrics Name Space
(PMNS), and an internal identifier, the Performance Metric Identifier
A PMNS specifies the association between a metric's name and its
A PMNS is defined on one or more ASCII source files.
Loading of a PMNS is done by calling pmLoadNameSpace(3) or
As of Version 3.10.3 of PCP, by default duplicate names for the same
PMID are allowed in the PMNS, although pmLoadASCIINameSpace(3)
provides an alternative interface with user-defined control over the
processing of duplicate names in the PMNS. The external format for a
PMNS conforms to the syntax and semantics described in the following
There is one default PMNS in the files below $PCP_VAR_DIR/pmns,
although users and application developers are free to create and use
alternate PMNS's. For an example of this, see the PCP Tutorial in
Although an application can call pmLoadNameSpace(3), normally this is
only done directly for the -n command line option where an explicit
root PMNS file is specified. Since PCP version 2 uses a distributed
PMNS (see below), an application can extract PMNS information from a
host's PMCD or an archive. If the PMNS source is a version 1 archive
(see PCPIntro(1)), however, then the local PMNS will be loaded using
the path specified by the environment variable PMNS_DEFAULT.
In PCP version 1, the PMNS functions in the API all operated on a
PMNS loaded locally from a file. Since PCP version 2, however, PMNS
functions may get the PMNS information remotely from a PMCD or
directly from the meta data of an archive.
The PMNS specification is initially passed through pmcpp(1). This
means the following facilities may be used in the specification
+ C-style comments
+ #include directives
+ #define directives and macro substitution
+ conditional processing via #ifdef ... #endif, etc.
When pmcpp(1) is executed, the ``standard'' include directories are
the current directory and $PCP_VAR_DIR/pmns.
The pre-processing with pmcpp(1) may be omitted in some cases where
the PMNS is known to not contain any C-style comments, preprocessor
directives or macros. Refer to the descriptions of
pmLoadASCIINameSpace(3) and pmLoadNameSpace(3) for details.
The general syntax for a non-leaf node in the PMNS is as follows
Where pathname is the full pathname from the root of the PMNS to this
non-leaf node, with each component in the pathname separated by a
``.''. The root node for the PMNS must have the special name
``root'', but the common prefix ``root.'' must be omitted from all
pathnames. Each component in the pathname must begin with an
alphabetic character, and be followed by zero or more characters
drawn from the alphabetics, the digits and the underscore ``_'')
character. For alphabetic characters in a pathname component, upper
and lower case are distinguished.
Non-leaf nodes in the PMNS may be defined in any order.
The descendent nodes are defined by the set of names, relative to the
pathname of their parent non-leaf node. For the descendent nodes,
leaf nodes have a pmid specification, non-leaf nodes do not. The
syntax for the pmid specification has been chosen to help manage the
allocation of PMIDs across disjoint and autonomous domains of
administration and implementation. Each pmid consists of 3 integer
parts, separated by colons, e.g. 14:27:11. This hierarchic numbering
scheme is intended to mirror the implementation hierarchy of
performance metric domain, metrics cluster (data structure or
operational similarity) and individual metric. In practice, the two
leading components are likely to be macros in the PMNS specification
source, and pmcpp(1) will convert the macros to integers. These
macros for the initial components of the pmid are likely to be
defined either in a standard include file, e.g.
$PCP_VAR_DIR/pmns/stdpmid, or in the current source file.
To support dynamic metrics, where the existence of a metric is known
to a PMDA, but not visible in the PMNS, a variant syntax for the pmid
is supported, namely a domain number followed by asterisks for the
other components of the pmid, e.g. 14:*:*. The corresponding metric
name forms the root of a subtree of dynamic metric names defined in
the corresponding PMDA as identified by the domain number.
The current allocation of the high-order (PMD or domain) component of
PMIDs is as follows.
│ Range │ Allocation │
│ 0 │ reserved │
│ 1-384 │ production PMDAs from PCP packages │
│385-510 │ end-user PMDAs (allocate from high to low) │
│ 511 │ reserved for dynamic PMNS entries │
This page is part of the PCP (Performance Co-Pilot) project.
Information about the project can be found at ⟨http://www.pcp.io/⟩.
If you have a bug report for this manual page, send it to
firstname.lastname@example.org. This page was obtained from the project's upstream
Git repository ⟨git://git.pcp.io/pcp⟩ on 2017-03-13. If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page, or
you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a mail
Performance Co-Pilot PCP PMNS(5)