NAME | C++ SYNOPSIS | DESCRIPTION | CONSTRUCTORS | DESCRIPTOR LOOKUP | SEE ALSO | DIAGNOSTICS | COLOPHON

QMC_CONTEXT(3)            Library Functions Manual            QMC_CONTEXT(3)

NAME         top

       QmcContext - container for a PMAPI context and its metrics

C++ SYNOPSIS         top

       #include <QmcContext.h>

       CC ... -lqmc -lpcp

DESCRIPTION         top

       A QmcContext object is a container for a single PMAPI(3) context.
       The object maintains a list of all the metric descriptors (QmcDesc),
       instance domains (QmcIndom) and metrics (QmcMetric) using the context
       to minimize the duplication of these objects.

CONSTRUCTORS         top

       A QmcContext object should be constructed through the QmcGroup::use
       interface.

DESCRIPTOR LOOKUP         top

       The metric and instance domain descriptors are cached by the
       QmcContext object to reduce duplicate QmcDesc(3) and QmcIndom(3)
       objects and PMAPI(3) calls required to create them.  Also the mapping
       from metrics names to pmIDs is also maintained to avoid
       pmLookupName(3) calls.

       int lookupDesc(const char *name, pmID& id);
           Search for the metric name in the name list and set id to the
           known pmID.  If not found, use pmLookupName(3) to get the
           mapping.  If this call fails, the PMAPI(3) error code will be
           returned.

       int lookupDesc(const char *name, uint_t& desc, uint_t& indom);
           Find the index desc and indom to the QmcDesc object and the
           QmcIndom object for the metric name.  The indexes can then be
           used with QmcContext::desc and QmcContext::indom to obtain
           references to the real objects.  The methods will return a
           PMAPI(3) error code if the metric descriptor or instance domain
           could not be obtained.

       int lookupDesc(pmID pmid, uint_t& desc, uint_t& indom);
           Find the index desc and indom to the QmcDesc object and the
           QmcIndom object for the metric pmid.  The indexes can then be
           used with QmcContext::desc and QmcContext::indom to obtain
           references to the real objects.  The methods will return a
           PMAPI(3) error code if the metric descriptor or instance domain
           could not be obtained.

SEE ALSO         top

       PMAPI(3), QMC(3), QmcDesc(3), QmcGroup(3), QmcIndom(3), QmcMetric(3),
       pmflush(3), pmLookupName(3) and pmprintf(3).

DIAGNOSTICS         top

       Error messages are generated using pmprintf(3) but are not flushed.
       It is the responsibility of the user to call pmflush(3) to output any
       messages.

       Additional diagnostics may be activated by adding DBG_TRACE_PMC and
       DBG_TRACE_OPTFETCH to the global pmDebug.

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 page, send it to
       pcp@oss.sgi.com.  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
       to man-pages@man7.org

Performance Co-Pilot                 SGI                      QMC_CONTEXT(3)