NAME
pmval - performance metrics value dumper
SYNOPSIS
pmval [-dgrz] [-A align] [-a archive] [-f N] [-h host] [-i instances]
[-K spec] [-n pmnsfile] [-O offset] [-p port] [-S starttime] [-s
samples] [-T endtime] [-t interval] [-U archive] [-w width] [-Z
timezone] metricname
DESCRIPTION
pmval prints current or archived values for the nominated performance
metric. The metric of interest is named in the metricname argument,
subject to instance qualification with the -i flag as described below.
Unless directed to another host by the -h option, or to an archive by
the -a or -U options, pmval will contact the Performance Metrics
Collector Daemon (PMCD) on the local host to obtain the required
information.
The metricname argument may also be given in the metric specification
syntax, as described in PCPIntro(1), where the source, metric and
instance may all be included in the metricname, e.g.
thathost:kernel.all.load["1 minute"]. When this format is used, none
of the -h or -a or -U options maye be specificed.
When using the metric specification syntax, the ‘‘hostname’’ @ is
treated specially and causes pmval to use a local context to collect
metrics from PMDAs on the local host without PMCD. Only some metrics
are available in this mode.
When processing an archive, pmval may relinquish its own timing
control, and operate as a ‘‘slave’’ of a pmtime(1) process that uses a
GUI dialog to provide timing control. In this case, either the -g
option should be used to start pmval as the sole slave of a new
pmtime(1) instance, or -p should be used to attach pmval to an existing
pmtime(1) instance via the IPC channel identified by the port argument.
The -S, -T, -O and -A options may be used to define a time window to
restrict the samples retrieved, set an initial origin within the time
window, or specify a ‘‘natural’’ alignment of the sample times; refer
to PCPIntro(1) for a complete description of these options.
Options which control the source, timing and layout of the information
reported by pmval are as follows:
-a Performance metric values are retrieved from the Performance Co-
Pilot (PCP) archive log file identified by the base name archive.
-d When replaying from an archive, this option requests that the
prevailing real-time delay be applied between samples (see -t) to
effect a pause, rather than the default behaviour of replaying at
full speed.
-f Numbers are reported in ‘‘fixed point’’ notation, rather than the
default scientific notation. Each number will be up to the column
width determined by the default heuristics, else the -w option if
specified, and include N digits after the decimal point. So, the
options -f 3 -w 8 would produce numbers of the form 9999.999. A
value of zero for N omits the decimal point and any fractional
digits.
-g Start pmval as the slave of a new pmtime(1) process for replay of
archived performance data using the pmtime(1) graphical user
interface.
-h Current performance metric values are retrieved from the nominated
host machine.
-i instances is a list of one or more instance names for the
nominated performance metric - just these instances will be
retrieved and reported (the default is to report all instances).
The list must be a single argument, with elements of the list
separated by commas and/or white space.
The instance name may be quoted with single (’) or double (")
quotes for those cases where the instance name contains white
space or commas.
Multiple -i options are allowed as an alternative way of
specifying more than one instance of interest.
As an example, the following are all equivalent:
$ pmval -i "’1 minute’,’5 minute’" kernel.all.load
$ pmval -i ’"1 minute","5 minute"’ kernel.all.load
$ pmval -i "’1 minute’ ’5 minute’" kernel.all.load
$ pmval -i "’1 minute’" -i "’5 minute’" kernel.all.load
$ pmval ’localhost:kernel.all.load["1 minute","5 minute"]’
-K When fetching metrics from a local context, the -K option may be
used to control the DSO PMDAs that should be made accessible. The
spec argument conforms to the syntax described in
__pmSpecLocalPMDA(3). More than one -K option may be used.
-n Normally pmval operates on the default Performance Metrics Name
Space (PMNS), however if the -n option is specified an alternative
namespace is loaded from the file pmnsfile.
-p Attach pmval to an existing pmtime(1) time control process
instance via the IPC channel identified by the port argument.
This option is normally only used by other tools, e.g.
pmchart(1), when they launch pmval with synchronized time control.
-r Print raw values for cumulative counter metrics. Normally
cumulative counter metrics are converted to rates. For example,
disk transfers are reported as number of disk transfers per second
during the preceding sample interval, rather than the raw value of
number of disk transfers since the machine was booted. If you
specify this option, the raw metric values are printed.
-s The argument samples defines the number of samples to be retrieved
and reported. If samples is 0 or -s is not specified, pmval will
sample and report continuously (in real time mode) or until the
end of the PCP archive (in archive mode).
-t The default update interval may be set to something other than the
default 1 second. The interval argument follows the syntax
described in PCPIntro(1), and in the simplest form may be an
unsigned integer (the implied units in this case are seconds).
-U Performance metric values are retrieved from the Performance Co-
Pilot (PCP) archive log file identified by the base name archive,
although unlike -a every recorded value in the archive for the
selected metric and instances is reported (so no interpolation
mode, and the sample interval (-t option) is ignored.
At most one of the options -a and -U may be specified.
-w Set the width of each column of output to be width columns. If
not specified columns are wide enough to accommodate the largest
value of the type being printed.
-Z By default, pmval reports the time of day according to the local
timezone on the system where pmval is run. The -Z option changes
the timezone to timezone in the format of the environment variable
TZ as described in environ(5).
-z Change the reporting timezone to the local timezone at the host
that is the source of the performance metrics, as identified via
either the metricname or the -h or -a or -U options.
The following symbols may occasionally appear, in place of a metric
value, in pmval output: A question mark symbol (?) indicates that a
value is no longer available for that metric instance. An exclamation
mark (!) indicates that a 64-bit counter wrapped during the sample.
The output from pmval is directed to standard output.
FILES
$PCP_VAR_DIR/pmns/*
default PMNS specification files
PCP ENVIRONMENT
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(4).
SEE ALSO
PCPIntro(1), pmcd(1), pmchart(1), pmdumplog(1), pminfo(1), pmlogger(1),
pmtime(1), PMAPI(3), __pmSpecLocalPMDA(3), pcp.conf(4) and pcp.env(4).
DIAGNOSTICS
All are generated on standard error and are intended to be self-
explanatory.
CAVEATS
By default, pmval attempts to display non-integer numeric values in a
way that does not distort the inherent precision (rarely more than 4
significant digits), and tries to maintain a tabular format in the
output. These goals are sometimes in conflict.
In the absence of the -f option (described above), the following table
describes the formats used for different ranges of numeric values for
any metric that is of type PM_TYPE_FLOAT or PM_TYPE_DOUBLE, or any
metric that has the semantics of a counter (for which pmval reports the
rate converted value):
+----------+----------------------+
| Format | Value Range |
+----------+----------------------+
| ! | No values available |
|9.999E-99 | < 0.1 |
| 0.0 | 0 |
| 9.9999 | > 0 and <= 0.9999 |
| 9.999 | > 0.9999 and < 9.999 |
| 99.99 | > 9.999 and < 99.99 |
| 999.9 | > 99.99 and < 999.9 |
|9999. | > 999.9 and < 9999 |
|9.999E+99 | > 9999 |
+----------+----------------------+