NAME | C SYNOPSIS | DESCRIPTION | SEE ALSO | FILES | DIAGNOSTICS | COLOPHON

PMAFM(3)                  Library Functions Manual                  PMAFM(3)

NAME         top

       pmafm,  pmRecordSetup, pmRecordAddHost, pmRecordControl - record mode
       support for PMAPI clients

C SYNOPSIS         top

       #include <pcp/pmafm.h>

       FILE *pmRecordSetup(const char *folio, const char *creator,
               int replay);
       int pmRecordAddHost(const char *host, int isdefault,
               pmRecordHost **rhp);
       int pmRecordControl(pmRecordHost *rhp, int request,
               const char *options);

       cc ... -lpcp_gui

DESCRIPTION         top

       These routines may be used to create a Performance Co-Pilot (PCP)
       archive ``on the fly'' to support ``record mode'' services for PMAPI
       client applications.

       Each record mode ``session'' involves one or more PCP archive logs
       each created using a dedicated pmlogger(1) process, with an overall
       Archive Folio format as understood by pmafm(1), to name and collect
       all of the archive logs associated with a single recording session.

       The pmRecordHost structure is used to maintain state information
       between the creator of the recording session and the associated
       pmlogger process(es).  The structure is defined as:
         typedef struct {
             FILE   *f_config;    /* caller writes pmlogger configuration here */
             int    fd_ipc;       /* IPC channel to pmlogger */
             char   *logfile;     /* full pathname for pmlogger error logfile */
             pid_t  pid;          /* process id for pmlogger */
             int    status;       /* exit status, -1 if unknown */
         } pmRecordHost;

       The routines are used in combination to create a recording session as
       follows.

       1.  Call pmRecordSetup to establish a new recording session.  A new
           Archive Folio will be created using the name folio; if the file
           or directory folio already exists, or the file folio cannot be
           created, this is an error.  The application that is creating the
           session is identified by creator (most often this would be the
           same as the global PMAPI application name, pmProgname).  If the
           application knows how to create its own configuration file to
           replay the recorded session, then replay should be non-zero.

           pmRecordSetup returns a stdio stream onto which the application
           should write the text of the required replay configuration file,
           if any.

       2.  For each host that is to be included in the recording session,
           call pmRecordAddHost.  A new pmRecordHost structure is returned
           via rhp.  It is assumed that pmcd(1) is running on host as this
           is how pmlogger(1) will retrieve the required performance
           metrics.

           If this host is the default host for this recording session, then
           isdefault should be non-zero.  This will ensure that the
           corresponding archive appears first in the PCP archive folio, and
           hence the tools used to replay the archive folio will make the
           correct determination of the archive associated with the default
           host.  At most one host per recording session may be nominated as
           the default host.

           The calling application should write the desired pmlogger
           configuration onto the stdio stream returned via the f_config
           field in the pmRecordHost structure.

       3.  Optionally add arguments to the command line that will be used to
           launch pmlogger(1) by calling pmRecordControl with a request of
           PM_REC_SETARG.  The argument is passed via options and one call
           to pmRecordControl is required for each distinct argument.

           An argument may be added for a particular pmlogger instance
           identified by rhp, or if the rhp argument is NULL the argument is
           added for all pmlogger instances that will be launched in the
           current recording session.

           Independent of any calls to pmRecordControl with a request of
           PM_REC_SETARG, each pmlogger instance will automatically be
           launched with the following arguments: -c, -h, -l, -x and the
           basename for the PCP archive log.

       4.  To commence the recording session, call pmRecordControl with a
           request of PM_REC_ON, and rhp must be NULL.  This will launch one
           pmlogger(1) process for each host in the recording session, and
           initialize the fd_ipc, logfile, pid and status fields in the
           associated pmRecordHost structure(s).

       5.  To terminate a pmlogger instance identified by rhp, call
           pmRecordControl with a request of PM_REC_OFF.  If the rhp
           argument to pmRecordControl is NULL, the termination request is
           broadcast to all pmlogger processes in the current recording
           session.

           An informative dialog is generated directly by each pmlogger
           process and hence note the comments on the disposition of output
           from pmlogger below.

           Alternatively, pmlogger can be started with options to limit the
           duration of logging, e.g. the -T or -s arguments, in which case
           there is no need to call pmRecordControl with a request of
           PM_REC_OFF and no dialog is generated.

       6.  To display the current status of the pmlogger instance identified
           by rhp, call pmRecordControl with a request of PM_REC_STATUS.  If
           the rhp argument to pmRecordControl is NULL, the status request
           is broadcast to all pmlogger processes in the current recording
           session.

           The display is generated directly by each pmlogger process and
           hence note the comments on the disposition of output from
           pmlogger below.

       7.  To detach a pmlogger instance identified by rhp and allow it to
           continue independent of the application that launched the
           recording session, call pmRecordControl with a request of
           PM_REC_DETACH.  If the rhp argument to pmRecordControl is NULL,
           the detach request is broadcast to all pmlogger processes in the
           current recording session.

           An informative dialog is generated directly by each pmlogger
           process and hence note the comments on the disposition of output
           from pmlogger below.

       The calling application should not close any of the returned stdio
       streams; this will be done by pmRecordControl when recording is
       commenced.

       Once pmlogger has been started for a recording session, then pmlogger
       will assume responsibility for any dialog with the user in the event
       that the application that launched the recording session should exit,
       particularly without terminating the recording session.

       By default, information and dialogs from pmlogger will be displayed
       using pmquery(1) on the assumption that most applications wishing to
       launch a recording session are GUI-based.  In the event that pmquery
       fails to display the information (for example, because the DISPLAY
       environment variable is not set), pmlogger will write on its own
       stderr stream (not the stderr stream of the launching process); the
       output will be assigned to the XXXXXX.host.log file described in the
       FILES section below.  For convenience, the full pathname to this file
       is provided via the logfile field in the pmRecordHost structure.

       If the options argument to pmRecordControl is not NULL, this string
       may be used to pass additional arguments to pmquery(1) in those cases
       where a dialog is to be displayed.  One use of this capability would
       be to provide a -geometry string to control the placement of the
       dialog.

       Premature termination of a launched pmlogger process may be
       determined using the pmRecordHost structure, by calling select(2) on
       the fd_ipc field or polling the status field that will contain the
       termination status from waitpid(2) if known, else -1.

SEE ALSO         top

       pmafm(1), pmlogger(1), pmquery(1) and PMAPI(3).

FILES         top

       These routines create a number of files in the same directory as the
       folio file named in the call to pmRecordSetup.  In all cases, the
       ``XXXXXX'' component is the result of calling mktemp(3).

       XXXXXX    If replay is non-zero, this is the creator's replay
                 configuration file, else an empty control file, used to
                 guarantee uniqueness.
       folio     The PCP Archive Folio, suitable for use with pmafm(1).
       XXXXXX.host.config
                 The pmlogger(1) configuration for each host - if the same
                 host is used in different calls to pmRecordAddHost within
                 the same recording session then one of the letters ``a''
                 through ``z'' will be appended to the ``XXXXXX'' part of
                 all associated file names to ensure uniqueness.
       XXXXXX.host.log
                 stdout and stderr for the pmlogger(1) instance for each
                 host.
       XXXXXX.host.{0,meta,index}
                 The files comprising a single PCP archive for each host.

DIAGNOSTICS         top

       pmRecordSetup may return NULL in the event of an error.  Check errno
       for the real cause, but the value EINVAL typically means that the
       order of calls to these routines is not correct (there is obvious
       state associated with the current recording session that is
       maintained across calls to these routines).  For example the
       following calls would produce this EINVAL error; calling
       pmRecordControl before calling pmRecordAddHost at least once, or
       calling pmRecordAddHost before calling pmRecordSetup.

       pmRecordControl and pmRecordAddHost both return 0 on success, else a
       value less than 0 suitable for decoding with pmErrStr(3) on failure.
       The value -EINVAL has the same interpretation as errno being set to
       EINVAL as described above.

       pmRecordControl will return PM_ERR_IPC if the associated pmlogger
       process has already exited.

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 2017-07-05.  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                 PCP                            PMAFM(3)

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