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NAME | C SYNOPSIS | CAVEAT | DESCRIPTION | RETURN VALUE | SEE ALSO | COLOPHON |
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PMLOCALPMDA(3) Library Functions Manual PMLOCALPMDA(3)
__pmLocalPMDA - change the table of DSO PMDAs for
PM_CONTEXT_LOCAL contexts
#include "pmapi.h"
#include "libpcp.h"
int __pmLocalPMDA(int op, int domain, const char *name,
const char *init);
cc ... -lpcp
This documentation is intended for internal Performance Co-Pilot
(PCP) developer use.
These interfaces are not part of the PCP APIs that are guaranteed
to remain fixed across releases, and they may not work, or may
provide different semantics at some point in the future.
PCP contexts of type PM_CONTEXT_LOCAL are used by clients that
wish to fetch metrics directly from one or more PMDAs on the lo‐
cal host without involving pmcd(1). A PMDA that is to be used in
this way must have been built as a Dynamic Shared Object (DSO).
Historically the table of PMDAs available for use with PM_CON‐
TEXT_LOCAL was hardcoded to the following:
* The PMDA (or PMDAs) that export the operating system perfor‐
mance data and data about process activity.
* The mmv PMDA.
* The sample PMDA provided $PCP_LITE_SAMPLE or $PMDA_LOCAL_SAMPLE
is set in the environment - used mostly for QA and testing.
The initial table of PMDAs available for use with PM_CONTEXT_LO‐
CAL is now generated dynamically from all those PMDAs that have
been installed as DSOs on the local host. The one exception is
the ``pmcd'' PMDA which only operates correctly in the address
space of a running pmcd(1) process and so is not available to an
application using a PM_CONTEXT_LOCAL context.
__pmLocalPMDA provides a number of services to amend the table of
PMDAs available for use with PM_CONTEXT_LOCAL.
The op argument specifies the what should be done and takes one
of the following values and actions:
PM_LOCAL_ADD Append an entry to the table for the PMDA with a
Performance Metrics Domain (PMD) of domain, the
path to the DSO PMDA is given by path and the PM‐
DA's initialization routine is init.
PM_LOCAL_DEL Removes all entries in the table where the domain
matches, or the path matches. Setting the argu‐
ments domain to -1 or path to NULL to force
matching on the other argument. The init argu‐
ment is ignored.
PM_LOCAL_CLEAR Remove all entries from the table. All the other
arguments are ignored in this case.
The domain, name and init arguments have similar syntax and se‐
mantics to the associated fields in the pmcd(1) configuration
file. The one difference is the path argument which is used by
__pmLocalPMDA to find a likely looking DSO by searching in this
order: $PCP_PMDAS_DIR/path, path, $PCP_PMDAS_DIR/path.dso-suffix
and finally path.dso-suffix (dso-suffix is the local platform
specific default file name suffix for a DSO, e.g. so for Linux,
dylib for Mac OS X, dll for Windows, etc.).
In most cases, __pmLocalPMDA returns 0 to indicate success. If
op is invalid, then the return value is PM_ERR_CONV else if there
is no matching table entry found for a PM_LOCAL_DEL operation,
PM_ERR_INDOM is returned.
pmcd(1), PMAPI(3), pmNewContext(3) and __pmSpecLocalPMDA(3).
This page is part of the PCP (Performance Co-Pilot) project. In‐
formation about the project can be found at ⟨http://www.pcp.io/⟩.
If you have a bug report for this manual page, send it to
pcp@groups.io. This page was obtained from the project's
upstream Git repository
⟨https://github.com/performancecopilot/pcp.git⟩ on 2024-06-14.
(At that time, the date of the most recent commit that was found
in the repository was 2024-06-14.) 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 to
man-pages@man7.org
Performance Co-Pilot PMLOCALPMDA(3)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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