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NAME | SYNOPSIS | DESCRIPTION | ACCESS CONTROL | PCP ENVIRONMENT | SEE ALSO | DIAGNOSTICS | CAVEAT | COLOPHON |
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PMLC(1) General Commands Manual PMLC(1)
pmlc - configure active Performance Co-Pilot pmlogger(s) interac‐
tively
pmlc [-e] [-h host] [-i] [-n pmnsfile] [-P] [-p port] [-Z timezone]
[-z] [pid]
pmlc may be used to change those metrics and instances which a
pmlogger(1) writes to a Performance Co-Pilot archive (see
PCPIntro(1)), the frequency with which the metrics are collected and
whether the logging is mandatory, advisory, on or off. It also
reports the current logging status of metrics and instances. pmlc
may be used to control pmlogger instances on remote hosts as well as
those on the local host.
Normally pmlc operates on the distributed Performance Metrics Name
Space (PMNS), however if the -n option is specified an alternative
local PMNS is loaded from the file pmnsfile.
If the -P option is specified, pmlc will attempt to start with a
connection to the primary pmlogger on the local host. If the -p
option is specified, then pmlc will attempt to start with a
connection to the pmlogger on this TCP/IP port. Alternatively, if
pid is specified, a connection to the pmlogger instance with that
process id will be attempted on startup. The -h option may only be
used if -P, -p port or a pid is also specified. In that case pmlc
will initially connect to the specified (remote) pmlogger instance on
host rather than the local host. If the connection to the specified
pmlogger instance cannot be established, pmlc will start with no
connection. These options typically allow the same file of pmlc
commands to be directed to multiple pmlogger instances by varying the
command line arguments. Note that -P, -p port, pid and -h are used
only when making an initial connection to a pmlogger instance. They
are not used as defaults if subsequent connections are made
interactively (see the connect command below).
By default, pmlc reports the time of day according to the local
timezone on the system where pmlc is run. The -Z option changes the
timezone to timezone in the format of the environment variable TZ as
described in environ(7). The -z option changes the timezone to the
timezone of the pmlogger instance from which information is being
obtained. Only one of -z or -Z may be specified.
If standard input is from a tty, pmlc is interactive, with prompts.
The -i flag may be used to force interactive behavior, and is
typically used in conjunction with -e to echo all command input on
standard output.
The following commands may be used:
show [ loggers ] [ @host ]
Displays the process identities of all pmlogger instances running
on the local host (or host, if specified). The primary pmlogger
pid is parenthesized because it can be referred to as "primary"
as well as by its pid.
connect pid [ @host ]
connect primary [ @host ]
Connects pmlc to the specified pmlogger process. Any existing
connection to a pmlogger instance is closed first. Each pmlogger
instance will accept at most one connection at a time, so if the
connection is successfully established, your pmlc will be the
only one controlling the pmlogger instance it is connected to.
new volume
This command works only while a connection to a pmlogger instance
is established. It tells the pmlogger to close the current
volume of the log and open a new volume. Closed volumes may be
archived, e.g. as part of a regular log management procedure to
control the size of the physical log files.
status
This command works only while a connection to a pmlogger instance
is established. It prints information about the state of the
pmlogger instance and its associated log.
timezone local | logger | "timezone"
This command sets the time zone used when times are printed.
local means use the time zone of the machine that pmlc is running
on. logger means use the time zone of the machine where the
pmlogger instance is running. Alternatively an explicit timezone
enclosed in quotes may be supplied (refer to TZ in environ(7) for
details). The default time zone is local unless one of the -z or
-Z options has been supplied on the command line.
flush
This command works only while a connection to a pmlogger instance
is established, and requests the pmlogger instance to flush to
disk all buffers associated with the current archive. For old-
timers, sync is a synonym for flush. In current versions of
pmlogger(1) all writes are unbuffered and aligned with the
logical records in the external files, so this command achieves
nothing, but is retained for backwards compatibility.
help
Displays a summary of the available commands.
h and ? are synonyms for help.
quit
Exits from pmlc.
The remaining commands query and change the logging state of metrics
and instances. They will work only if pmlc has a connection to a
pmlogger instance. Metrics may be specified as fully qualified names
(e.g. hinv.ncpu) or subtrees of the PMNS (e.g. hinv) which are
expanded to include all metrics in the subtree (e.g. hinv.ncpu,
hinv.cpuclock, etc.). Lists of metrics may be specified by enclosing
them in braces with spaces or a comma between metrics (e.g.
{hinv.ncpu hinv.ndisk}). Subtrees of metrics may be included in such
lists.
Each individual metric specification may be further qualified with a
space or comma separated list of instances in square brackets (e.g.
kernel.all.load["1 minute", "5 minute"]). External instance names or
numeric internal instance identifiers or both may be used in the same
list (e.g. sample.colour.[red,1,"blue"]). If an instance
qualification is applied to a subtree of the PMNS all of the metrics
in the subtree must have the same instance domain. Instance
qualifications may not be applied to entire lists of metrics but may
appear inside such lists.
If no instances are specified for a metric, all instances are used.
All instances means all instances available at the time the pmlogger
instance in question fetches the metrics for logging. If an instance
domain changes over time this is not always the same as the set of
instances displayed by pmlc, which can only display the currently
available instances. To prevent unintentional errors, only the
instances that are currently available to pmlc may appear in instance
specifications.
query metriclist
The current logging state of each metric (and instances, where
applicable) in metriclist is displayed. This includes the
logging state (e.g. on, maybe, off) and the logging interval for
each metric (and instance) requested. The following
abbreviations pertaining to metrics (and instances) may appear in
the output: adv, advisory; mand, mandatory; nl, not in the log;
na, in the log but not currently available from its Performance
Metrics Domain Agent (PMDA). Where appropriate, an instance name
will appear last on a line preceded by its numeric internal
instance identifier.
[ log ] mandatory on interval metriclist
This form of the log command turns on logging for the metrics
(and any instances) in metriclist. interval specifies how often
the specified metrics/instances should be logged. once indicates
that the metrics/instances should appear at most once in the log.
More often one would use the optional keyword every followed by a
positive number and one of millisecond (or msec), second (or
sec), minute (or min), hour or their plurals.
Note that the keyword default which may be used for the default
interval in a pmlogger(1) configuration file cannot be used in
pmlc.
Internal limitations require the interval to be less than
(approximately) 74 hours. An interval value of zero is a synonym
for once.
[ log ] mandatory off metriclist
This tells the pmlogger instance not to log any of the
metrics/instances in metriclist.
[ log ] mandatory maybe metriclist
This tells the pmlogger instance to honor any subsequent advisory
logging requests for the metrics/instances in metriclist. If the
current logging state of the metrics/instances is mandatory
(either on or off) the new state will be set to maybe
(effectively advisory off). If the current state of the
metrics/instances is already advisory (either on or off) the
state(s) for the metrics/instances will remain as they are.
[ log ] advisory on interval metriclist
[ log ] advisory off metriclist
Advisory logging is only applicable if the last logging state
specified for a metric/instance was "mandatory maybe" (which
permits subsequent advisory logging control) or if the logging
state is already advisory. These two statements turn advisory
logging on or off (respectively) for the specified
metrics/instances.
The interpretation for interval is as above for the mandatory
case.
There is no continuation character required for commands that span
lines.
The word at may be used interchangeably with @.
A request to log all instances of a metric will supersede any prior
request to log either all or specific instances of a metric (if the
request specifies a permissible transition in the logging state). A
request to log specific instances of a metric when all instances of a
metric are already being logged is refused by pmlogger.
pmlc may have restricted access to and control over pmlogger(1)
processes.
If a pmlogger(1) is unable to export its control information to the
local pmcd(1), then that pmlogger(1) cannot cannot be connected to
nor controlled by pmlc. In practice, this means the pmlogger(1)
process has to be owned by the user ``pcp'' and/or the group ``pcp''.
If pmlogger(1) is running on the host ``foo'' then use ``pminfo -f -h
foo pmcd.pmlogger'' to verify that the pmlogger(1) of interest is
known to pmcd(1), alternatively pmlogger(1) instances that are not
reported from the pmlc show loggers @foo command are not known to
pmcd(1) on the host ``foo''.
If pmlogger(1) is launched with a configuration file that contains an
[access] section, then pmlc will be unable to connect to that
pmlogger(1) unless the access controls allow some access from the
host where pmlc is being run. Minimally this requires the enquire
access to be permitted in the pmlogger(1) access control section.
If pmlc is able to connect to the pmlogger(1) of interest, then the
following table summarizes the permissions needed to perform
different pmlc commands:
┌──────────────────┬───────────────────────────────────────┐
│ pmlc command │ Required pmlogger access │
├──────────────────┼───────────────────────────────────────┤
│show loggers │ Any │
│connect │ Any of enquire, advisory or mandatory │
│status │ Any of enquire, advisory or mandatory │
│query ... │ Any of enquire, advisory or mandatory │
│log advisory ... │ advisory │
│log mandatory ... │ mandatory │
│new volume │ mandatory │
└──────────────────┴───────────────────────────────────────┘
Environment variables with the prefix PCP_ are used to parameterize
the file and directory names used by PCP. On each installation, the
file /etc/pcp.conf contains the local values for these variables.
The $PCP_CONF variable may be used to specify an alternative
configuration file, as described in pcp.conf(5).
PCPIntro(1), pmcd(1), pmdumplog(1), pmlogger(1), pcp.conf(5),
pcp.env(5) and environ(7).
Most error or warning messages are self-explanatory. A message of
the form
Warning: unable to change logging state for...
followed by a list of metrics (and possibly instances) indicates that
pmlogger refused the request for the metrics (and instances) that
appear. Any metrics (and instances) that were specified but do not
appear in the message have had their logging state updated
successfully (no news is good news). Usually this warning results
from requesting advisory logging when a mandatory control is already
in place, or requesting logging for specific instances when all
instances are already being logged.
If all instances of a metric are being logged and a request is made
to log specific instances of the metric with the same state and
frequency, the request may appear to succeed, even though pmlogger
has refused the request. This is not normally a problem, as the
required information will still be placed into the log by pmlogger.
However in the case where the metric is to be logged once, the
outcome is not what might be expected. When pmlogger receives a
request to log a metric once, it places the current value(s) of the
metric into the log as soon as it can, regardless of whether the
metric is already in the log. This may be used to force values into
the log. When a request to log specific instances of a metric
arrives and is refused because all instances of the metric are
already being logged, pmlogger does not place values for the
instances requested into the log. It returns the current logging
state for each instance requested to pmlc. The requested and
returned states are identical, so pmlc doesn't raise an error as it
should.
To ensure that only certain instances of a metric are being logged,
one should always turn off logging for all instances of the metric
prior to turning on logging for the specific instances required.
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@groups.io. This page was obtained from the project's upstream
Git repository ⟨https://github.com/performancecopilot/pcp.git⟩ on
2018-02-02. (At that time, the date of the most recent commit that
was found in the repository was 2018-02-02.) 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 PMLC(1)
Pages that refer to this page: pcpintro(1), pmlogextract(1), pmlogger(1), pmlogger_check(1), pmlogreduce(1), pmnewlog(1), pmsnap(1), __pmconnectlogger(3), __pmcontrollog(3)
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