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NAME | SYNOPSIS | DESCRIPTION | FILES | PCP ENVIRONMENT | SEE ALSO | DIAGNOSTICS | COLOPHON |
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PMSTAT(1) General Commands Manual PMSTAT(1)
pcp-vmstat, pmstat - high-level system performance overview
pcp [pcp options] vmstat [interval [samples]]
pmstat [-gLlPxz] [-A align] [-a archive] [-h host] [-H file] [-n
pmnsfile] [-O offset] [-p port] [-S starttime] [-s samples] [-T
endtime] [-t interval] [-Z timezone]
pmstat provides a one line summary of system performance every
interval unit of time (the default is 5 seconds). pmstat is intended
to monitor system performance at the highest level, after which other
tools may be used to examine subsystems in which potential
performance problems may be observed in greater detail.
pcp-vmstat is a simple wrapper for use with the pcp(1) command,
providing a more familiar command line format for some users. It
also enables the extended reporting option by default, see the -x
option below.
Multiple hosts may be monitored by supplying more than one host with
multiple -h flags (for live monitoring) or by providing a name of the
hostlist file, where each line contain one host name, with -H, or
multiple -a flags (for retrospective monitoring from sets of
archives).
The -t option may be used to change the default reporting interval.
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).
By default, pmstat fetches metrics by connecting to the Performance
Metrics Collector Daemon (PMCD) on the local host. If the -L option
is specified, then pmcd(1) is bypassed, and metrics are fetched from
PMDAs on the local host using the standalone PM_CONTEXT_LOCAL variant
of pmNewContext(3). When the -h option is specified, pmstat connects
to the pmcd(1) on host and fetches metrics from there. As mentioned
above, multiple hosts may be monitored by supplying multiple -h
flags.
Alternatively, if the -a option is used, the metrics are retrieved
from the Performance Co-Pilot archive log files identified by
archive, which is a comma-separated list of names, each of which may
be the base name of an archive or the name of a directory containing
one or more archives. Multiple sets of archives may be replayed by
supplying multiple -a flags. When the -a flag is used, the -P flag
may also be used to pause the output after each interval.
Standalone mode can only connect to the local host, using a set of
archives implies a host name, and nominating a host precludes using
an archive, so the options -L, -a and -h are mutually exclusive.
Normally pmstat 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.
If the -s the option is specified, samples defines the number of
samples to be retrieved and reported. If samples is 0 or -s is not
specified, pmstat will sample and report continuously - this is the
default behavior.
When processing a set of archives, pmstat 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 pmstat as the sole slave
of a new pmtime(1) instance, or -p should be used to attach pmstat 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.
The -l option prints the last 7 characters of a hostname in summaries
involving more than one host (when more than one -h option has been
specified on the command line).
The -x option (extended CPU metrics) causes two additional CPU
metrics to be reported, namely wait for I/O ("wa") and virtualisation
steal time ("st").
The output from pmstat is directed to standard output, and the
columns in the report are interpreted as follows:
loadavg The 1 minute load average.
memory The swpd column indicates average swap space used during
the interval, in Kbytes. The free column indicates average
free memory during the interval, in Kbytes. The buff
column indicates average buffer memory in use during the
interval, in Kbytes. The cache column indicates average
cached memory in use during the interval, in Kbytes.
If the values become large, they are reported as Mbytes (m
suffix) or Gbytes (g suffix).
swap The metrics in this area of the kernel instrumentation are
of varying value. We try to report the average number of
pages that are paged in (pi) and out (po) per second during
the interval. If the corresponding page swapping metrics
are unavailable, we report the average rate per second of
swap operations in (si) and out (so) during the interval.
It is normal for the ``in'' values to be non-zero, but the
system is suffering memory stress if the ``out'' values are
non-zero over an extended period.
If the values become large, they are reported as thousands
of operations per second (K suffix) or millions of
operations per second (M suffix).
io The bi and bo columns indicate the average rate per second
of block input and block output operations (respectfully)
during the interval. Unless all file systems have a 1
Kbyte block size, these rates do not directly indicate
Kbytes transferred.
If the values become large, they are reported as thousands
of operations per second (K suffix) or millions of
operations per second (M suffix).
system Interrupt rate (in) and context switch rate (cs). Rates
are expressed as average operations per second during the
interval. Note that the interrupt rate is normally at
least HZ (the clock interrupt rate, usually 100) interrupts
per second.
If the values become large, they are reported as thousands
of operations per second (K suffix) or millions of
operations per second (M suffix).
cpu Percentage of CPU time spent executing user and "nice user"
code (us), system and interrupt processing code (sy), idle
loop (id).
If any values for the associated performance metrics are unavailable,
the value appears as ``?'' in the output.
By default, pmstat reports the time of day according to the local
timezone on the system where pmstat 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 local timezone at the host that is the source of the performance
metrics, as identified via either the -h or -a options.
$PCP_VAR_DIR/pmns/*
default PMNS specification files
$PCP_VAR_DIR/config/pmlogger/config.pmstat
pmlogger(1) configuration for creating an archive suitable
for replay with pmstat
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), pmclient(1), pmtime(1), PMAPI(3), pmNewContext(3),
pcp.conf(5) and pcp.env(5).
All are generated on standard error, and are intended to be self-
explanatory.
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 PMSTAT(1)
Pages that refer to this page: pcpintro(1), pmcd(1), pmclient(1), pmrep(1), pmgetoptions(3)
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