поддержка режима записи для клиентов PMAPI (record mode support for PMAPI clients)
Имя (Name)
pmRecordSetup, pmRecordAddHost, pmRecordControl - record mode
support for PMAPI clients
Синопсис C (C Synopsis)
#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
Описание (Description)
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,
as returned by pmGetProgname(3)). 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.
Диагностика (Diagnostic)
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.
Файлы (Files)
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.
Смотри также (See also)
pmafm(1), pmlogger(1), pmquery(1) and PMAPI(3).
