| PMRECORD(3) | Library Functions Manual | PMRECORD(3) |
pmRecordSetup, pmRecordAddHost, pmRecordControl - record mode support for PMAPI clients
#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
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.
pmRecordSetup returns a stdio stream onto which the application should write the text of the required replay configuration file, if any.
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.
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.
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.
The display is generated directly by each pmlogger process and hence note the comments on the disposition of output from pmlogger below.
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.
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.
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).
pmafm(1), pmlogger(1), pmquery(1) and PMAPI(3).
| PCP | Performance Co-Pilot |