1PMLOCALPMDA(3) Library Functions Manual PMLOCALPMDA(3)
2
6 __pmLocalPMDA - change the table of DSO PMDAs for PM_CONTEXT_LOCAL con‐
7 texts
8
10 #include <pcp/pmapi.h>
11 #include <pcp/impl.h>
12 int __pmLocalPMDA(int op, int domain, const char *name, const char
14 *init)
15 cc ... -lpcp
17
19 PCP contexts of type PM_CONTEXT_LOCAL are used by clients that wish to
20 fetch metrics directly from one or more PMDAs on the local host without
21 involving pmcd(1). A PMDA that is to be used in this way must have
22 been built as a Dynamic Shared Object (DSO).
23 Historically the table of PMDAs available for use with PM_CONTEXT_LOCAL
25 was hardcoded to the following:
26 * The PMDA (or PMDAs) that export the operating system performance data
28 and data about process activity. On Irix, the per-process data was
29 only available if $PMDA_LOCAL_PROC is set in the environment.
30 * The mmv PMDA.
31 * The sample PMDA provided $PCP_LITE_SAMPLE or $PMDA_LOCAL_SAMPLE is
32 set in the environment - used mostly for QA and testing.
33 The initial table of PMDAs available for use with PM_CONTEXT_LOCAL is
35 now generated dynamically from all those PMDAs that have been installed
36 as DSOs on the local host. The one exception is the ``pmcd'' PMDA
37 which only operates correctly in the address space of a running pmcd(1)
38 process and so is not available to an application using a PM_CON‐
39 TEXT_LOCAL context.
40 __pmLocalPMDA provides a number of services to amend the table of PMDAs
42 available for use with PM_CONTEXT_LOCAL.
43 The op argument specifies the what should be done and takes one of the
45 following values and actions:
46 PM_LOCAL_ADD Append an entry to the table for the PMDA with a Per‐
48 formance Metrics Domain (PMD) of domain, the path to
49 the DSO PMDA is given by path and the PMDA's initial‐
50 ization routine is init.
51 PM_LOCAL_DEL Removes all entries in the table where the domain
53 matches, or the path matches. Setting the arguments
54 domain to -1 or path to NULL to force matching on the
55 other argument. The init argument is ignored.
56 PM_LOCAL_CLEAR Remove all entries from the table. All the other argu‐
58 ments are ignored in this case.
59 The domain, name and init arguments have similar syntax and semantics
61 to the associated fields in the pmcd(1) configuration file. The one
62 difference is the path argument which is used by __pmLocalPMDA to find
63 a likely looking DSO by searching in this order: $PCP_PMDAS_DIR/path,
64 path, $PCP_PMDAS_DIR/path.dso-suffix and finally path.dso-suffix (dso-
65 suffix is the local platform specific default file name suffix for a
66 DSO, e.g. so for Linux, dylib for Mac OS X, dll for Windows, etc.).
67
69 In most cases, __pmLocalPMDA returns 0 to indicate success. If op is
70 invalid, then the return value is PM_ERR_CONV else if there is no
71 matching table entry found for a PM_LOCAL_DEL operation, PM_ERR_INDOM
72 is returned.
73
75 pmcd(1), PMAPI(3), pmNewContext(3) and __pmSpecLocalPMDA(3).
76Performance Co-Pilot PMLOCALPMDA(3)