pmgenmap(1) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | FILES | PCP ENVIRONMENT | SEE ALSO | COLOPHON

PMGENMAP(1)              General Commands Manual             PMGENMAP(1)

NAME         top

       pmgenmap - generate C code to simplify handling of performance
       metrics

SYNOPSIS         top

       pmgenmap [infile]

DESCRIPTION         top

       Given one or more lists of metric names in infile or on standard
       input, pmgenmap generates C declarations and cpp(1) macros
       suitable for use across the Performance Metrics Programming
       Interface (PMAPI) on standard output.

       The declarations produced by pmgenmap simplify the coding for
       client applications using the PMAPI.

       The input should consist of one or more lists of metric names of
       the form

            listname {
                metricname1 symbolname1
                metricname2 symbolname2
                ...
            }

       which will generate C and cpp(1) declarations of the form

            char *listname[] = {
            #define symbolname1 0
                "metricname1",
            #define symbolname2 1
                "metricname2",
                ...
            };

       The array declarations produced are suitable as parameters to
       pmLookupName(3) and the #defined constants may be used to index
       the vsets in the pmResult structure returned by a pmFetch(3)
       call.

       Obviously, listname must conform to the C identifier naming
       rules, each symbolname must conform to the cpp(1) macro naming
       rules, and each metricname is expected to be a valid performance
       metrics name (see PMNS(5) for more details).

       The input may include sh-style comment lines, i.e. with a `#' as
       the first non-blank character of a line, and these are translated
       on output to either single line or multi-line C comments in the
       K&R style.  For example, the input:

            # leading block of multi-line comments
            # initialization group
            foo {
                    a.b.c   ONE
                    d.e.f.g TWO
                    # embedded block of multi-lines
                    # comments and boring pad text
                    xx.yy.zz        THREE
            }

            # trailing single line comment

       Produces the output:

            /*
             * leading block of multi-line comments
             * initialization group
             */
            char *foo[] = {
            #define ONE 0
                    "a.b.c",
            #define TWO 1
                    "d.e.f.g",
            /*
             * embedded block of multi-lines
             * comments and boring pad text
             */
            #define THREE 2
                    "xx.yy.zz",

            };

            /* trailing single line comment */

EXAMPLES         top

       For brevity we have removed the error handling code, and assumed
       the chosen metrics do not have multiple values.

       The input file

            mystats {
                kernel.percpu.cpu.idle     IDLE
                kernel.percpu.cpu.sys      SYS
                kernel.percpu.cpu.user     USER
                hinv.ncpu                       NCPU
            }

       produces the following C code, suitable for #include-ing

            /*
             * Performance Metrics Name Space Map
             * Built by pmgenmap from the file
             * mystats.metrics
             * on Wed Dec 28 19:44:17 EST 1994
             *
             * Do not edit this file!
             */

            char *mystats[] = {
            #define IDLE    0
                    "kernel.percpu.cpu.idle",
            #define SYS     1
                    "kernel.percpu.cpu.sys",
            #define USER    2
                    "kernel.percpu.cpu.user",
            #define NCPU    3
                    "hinv.ncpu",

            };

       Using the code generated by pmgenmap, we are now able to easily
       obtain metrics from the Performance Metrics Collection Subsystem
       (PMCS) as follows:

            #define MAX_PMID 4

                int         trip = 0;
                int         numpmid = sizeof(mystats)/sizeof(mystats[0]);
                double      duration;
                pmResult    *resp;
                pmResult    *prev;
                pmID        pmidlist[MAX_PMID];

                pmNewContext(PM_CONTEXT_HOST, "localhost");
                pmLookupName(numpmid, mystats, pmidlist);
                pmFetch(numpmid, pmidlist, &resp);

                printf("%d CPUs: %d usr   %d sys   %d   idle0,
                       resp->vset[NCPU]->vlist[0].value.lval,
                       resp->vset[USER]->vlist[0].value.lval,
                       resp->vset[SYS]->vlist[0].value.lval,
                       resp->vset[IDLE]->vlist[0].value.lval);

       Some calls to ensure portability have been removed from the code
       above for the sake of clarity - the example above should not be
       used as a template for programming.  In particular, the raw
       values of the metrics were used when pmLookupDesc(3) should have
       been called to determine the semantics of each metric.

       More complete examples that demonstrate the use of pmgenmap which
       may be used as a basis for program development are included in
       the PCP demos, e.g.  $PCP_DEMOS_DIR/pmclient.

FILES         top

       $PCP_VAR_DIR/pmns/*
            default PMNS specification files

PCP ENVIRONMENT         top

       Environment variables with the prefix PCP_ are used to
       parameterize the file and directory names used by PCP.  On each
       installation, the file /etc/pcp.conf contains the local values
       for these variables.  The $PCP_CONF variable may be used to
       specify an alternative configuration file, as described in
       pcp.conf(5).

SEE ALSO         top

       cpp(1), PMAPI(3), pmFetch(3), pmLookupName(3), pmNewContext(3),
       pcp.conf(5), pcp.env(5) and PMNS(5).

COLOPHON         top

       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
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       ⟨https://github.com/performancecopilot/pcp.git⟩ on 2021-04-01.
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Performance Co-Pilot               PCP                       PMGENMAP(1)

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