NAME

       QmcContext - container for a PMAPI context and its metrics

C++ SYNOPSIS

       #include <QmcContext.h>

       c++ ... -lpcp_qmc -lpcp

DESCRIPTION

       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

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

DESCRIPTOR LOOKUP

       The metric and instance domain descriptors are cached by the QmcContext object to reduce duplicate QmcDe‐
       sc(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 pm‐
           LookupName(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.

DIAGNOSTICS

       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 the options pmc and/or optfetch to the global debugging
       specification, as described in pmSetDebug(3).

SEE ALSO

       PMAPI(3), QMC(3), QmcDesc(3), QmcGroup(3), QmcIndom(3), QmcMetric(3), pmflush(3), pmLookupName(3) and pm‐
       printf(3).

Performance Co-Pilot                                   SGI                                         QMCCONTEXT(3)