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PCPINTRO(1) General Commands Manual PCPINTRO(1)
PCPIntro - introduction to the Performance Co-Pilot (PCP)
The Performance Co-Pilot (PCP) is a toolkit designed for
monitoring and managing system-level performance. These services
are distributed and scalable to accommodate the most complex
system configurations and performance problems.
PCP supports many different platforms, including (but not limited
to) Linux, MacOSX, Solaris and Windows. From a high-level PCP can
be considered to contain two classes of software utility:
PCP Collectors
These are the parts of PCP that collect and extract
performance data from various sources, for example the
operating system kernel.
PCP Monitors
These are the parts of PCP that display data collected
from hosts (or archives) that have the PCP Collector
installed. Many monitor tools are available as part of
the core PCP release, while other (typically graphical)
monitoring tools are available separately in the PCP GUI
package.
This manual entry describes the high-level features and options
common to most PCP utilities available on all platforms.
The PCP architecture is distributed in the sense that any PCP tool
may be executing remotely. On the host (or hosts) being
monitored, each domain of performance metrics, whether the kernel,
a service layer, a database management system, a web server, an
application, etc. requires a Performance Metrics Domain Agent
(PMDA) which is responsible for collecting performance
measurements from that domain. All PMDAs are controlled by the
Performance Metrics Collector Daemon (pmcd(1)) on the same host.
Client applications (the monitoring tools) connect to pmcd(1),
which acts as a router for requests, by forwarding requests to the
appropriate PMDA and returning the responses to the clients.
Clients may also access performance data from sets of PCP archives
(created using pmlogger(1)) for retrospective analysis.
Security philosophy
PCP redistributes a wealth of performance information within a
host and across its networks. The following security philosophy
underlies the setting of several defaults that control how much
information is sent and received.
By default, the information exposed by PMCD about a host is
approximately of the same level of confidentiality as available to
a completely unprivileged user on that host. So, performance data
that is available to be read completely freely on a machine may be
made available by PMCD to the network.
However, the host running PMCD and its network is not assumed to
run only friendly applications. Therefore, write type operations,
including from the local host, are not permitted by default.
These defaults may be overridden (expanded or reduced) in several
ways, including by specifying network ACLs in pmcd.conf,
activating non-default PMDAs, or by using PMCD connections that
pass user credentials. For example, some PMDAs automatically
provide greater information for particular credentialed users or
groups.
Applications
The following performance monitoring applications are primarily
console based, typically run directly from the command line, and
are just a small subset of the tools available as part of the base
PCP package.
Each tool or command is documented completely in its own reference
page.
pmstat Outputs an ASCII high-level summary of system performance.
pmie An inference engine that can evaluate predicate-action
rules to perform alarms and automate system management
tasks.
pminfo Interrogate specific performance metrics and the metadata
that describes them.
pmlogger
Generates PCP archives of performance metrics suitable for
replay by most PCP tools.
pmrep Highly customizable performance metrics reporter with
support for various different output modes.
pmval Simple periodic reporting for some or all instances of a
performance metric, with optional VCR time control.
If the PCP GUI package is installed then the following additional
tools are available.
pmchart
Displays trends over time of arbitrarily selected
performance metrics from one or more hosts.
pmtime Time control utility for coordinating the time between
multiple tools (including pmchart and pmval).
pmdumptext
Produce ASCII reports for arbitrary combinations of
performance metrics.
There is a set of common command line arguments that are used
consistently by most PCP tools.
-a archive, --archive=archive
Performance metric information is retrospectively retrieved
from the set of Performance Co-Pilot (PCP) archives
identified by archive previously generated by pmlogger(1).
See LOGIMPORT(3) and LOGARCHIVE(5) for archive creation
interfaces and format documentation.
archive is a comma-separated list of names, each of which
may be the name of a directory containing one or more
archives, the base name common to all of the physical files
created by an instance of pmlogger(1), or any one of the
physical files, e.g. /path/to/myarchives (directory) or
myarchive (base name) or myarchive.meta (the metadata file)
or myarchive.index (the temporal index) or myarchive.0 (the
first data volume of archive) or myarchive.0.bz2 or
myarchive.0.bz (the first data volume compressed with
bzip2(1)) or myarchive.0.gz or myarchive.0.Z or
myarchive.0.z (the first data volume compressed with
gzip(1)), myarchive.1 or myarchive.3.bz2 or myarchive.42.gz
etc.
-h host, --host=host
Unless directed to another host by the -h (or --host)
option, or to a set of archives by the -a (or --archive)
option, the source of performance metrics will be the
Performance Metrics Collector Daemon (PMCD) on the local
host. Refer to the PMCD HOST SPECIFICATION section later
for further details on the many options available when
forming the host specification, as well as a detailed
description of the default local host connection. The -a
(or --archive), and -h (or --host) options are mutually
exclusive.
-s samples, --samples=samples
The argument samples defines the number of samples to be
retrieved and reported. If samples is 0 or -s (or
--samples) is not specified, the application will sample
and report continuously (in real time mode) or until the
end of the set of PCP archives (in archive mode).
-z, --hostzone
Change the reporting timezone to the local timezone at the
host that is the source of the performance metrics, as
identified via either the -h (or --host) or -a (or
--archive) options.
-Z timezone, --timezone=timezone
By default, applications report the time of day according
to the local timezone on the system where the application
is executed. The -Z (or --timezone) option changes the
timezone to timezone in the format of the environment
variable TZ as described in environ(7).
-D debugspec, --debug=debugspec
Sets the PCP debugging options to debugspec to enable
diagnostics and tracing that is most helpful for developers
or when trying to diagnose the misbehaviour of a PCP
application. debugspec should be a comma-separated list of
debugging option name(s) and/or decimal integers, see
pmdbg(1) for a description of the supported option names
and values.
In the absence of a live or archive source of metrics, a heuristic
search for archives for the local host can be invoked via the -O
(or --origin) option. When using this option without an explicit
source of metrics, monitor tools attempt to use archives from a
system archive location such as $PCP_LOG_DIR/pmlogger/`hostname`.
Refer to the TIME WINDOW SPECIFICATION section below for details
on the acceptable syntax for the origin option, but a typical
invocation in this mode would be -O today or --origin yesterday.
Most PCP tools operate with periodic sampling or reporting, and
the -t (or --interval) and -A (or --align) options may be used to
control the duration of the sample interval and the alignment of
the sample times.
-t interval, --interval=interval
Set the update or reporting interval.
The interval argument is specified as a sequence of one or
more elements of the form
number[units]
where number is an integer or floating point constant
(parsed using strtod(3)) and the optional units is one of:
seconds, second, secs, sec, s, minutes, minute, mins, min,
m, hours, hour, h, days, day and d. If the unit is empty,
second is assumed.
In addition, the upper case (or mixed case) version of any
of the above is also acceptable.
Spaces anywhere in the interval are ignored, so 4 days 6
hours 30 minutes, 4day6hour30min, 4d6h30m and 4d6.5h are
all equivalent.
Multiple specifications are additive, for example ``1hour
15mins 30secs'' is interpreted as 3600+900+30 seconds.
-A align, --align=align
By default samples are not necessarily aligned on any
natural unit of time. The -A or --align option may be used
to force the initial sample to be aligned on the boundary
of a natural time unit. For example -A 1sec, -A 30min and
--align 1hour specify alignment on whole seconds, half and
whole hours respectively.
The align argument follows the syntax for an interval
argument described above for the -t or --interval option.
Note that alignment occurs by advancing the time as
required, and that -A (or --align) acts as a modifier to
advance both the start of the time window (see the next
section) and the origin time (if the -O or --origin option
is specified).
Many PCP tools are designed to operate in some time window of
interest, for example to define a termination time for real-time
monitoring or to define a start and end time within a set of PCP
archives.
In the absence of the -O (or --origin) and -A (or --align) options
to specify an initial sample time origin and time alignment (see
above), the PCP application will retrieve the first sample at the
start of the time window.
The following options may be used to specify a time window of
interest.
-S starttime, --start=starttime
By default the time window commences immediately in real-
time mode, or coincides with time at the start of the set
of PCP archives in archive mode. The -S or --start option
may be used to specify a later time for the start of the
time window.
The starttime parameter may be given in one of three forms
(interval is the same as for the -t or --interval option as
described above, datetime is described below):
interval
To specify an offset from the current time (in real-
time mode) or the beginning of a set of PCP archives
(in archive mode) simply specify the interval of
time as the argument. For example -S 30min will set
the start of the time window to be exactly 30
minutes from now in real-time mode, or exactly 30
minutes from the start of a set of PCP archives.
-interval
To specify an offset from the end of a set of PCP
archives, prefix the interval argument with a minus
sign. In this case, the start of the time window
precedes the time at the end of the set of archives
by the given interval. For example -S -1hour will
set the start of the time window to be exactly one
hour before the time of the last sample in a set of
PCP archives.
@datetime
To specify the calendar date and time (local time in
the reporting timezone) for the start of the time
window, use the datetime syntax preceded by an at
sign. Refer to the datetime description below for
detailed information.
-T endtime, --finish=endtime
By default the end of the time window is unbounded (in
real-time mode) or aligned with the time at the end of a
set of PCP archives (in archive mode). The -T or --finish
option may be used to specify an earlier time for the end
of the time window.
The endtime parameter may be given in one of three forms
(interval is the same as for the -t or --interval option as
described above, datetime is described below):
interval
To specify an offset from the start of the time
window simply use the interval of time as the
argument. For example -T 2h30m will set the end of
the time window to be 2 hours and 30 minutes after
the start of the time window.
-interval
To specify an offset back from the time at the end
of a set of PCP archives, prefix the interval
argument with a minus sign. For example -T -90m
will set the end of the time window to be 90 minutes
before the time of the last sample in a set of PCP
archives.
@datetime
To specify the calendar date and time (local time in
the reporting timezone) for the end of the time
window, use the datetime syntax preceded by an at
sign. Refer to the datetime description below for
detailed information.
-O origin, --origin=origin
By default samples are fetched from the start of the time
window (see description of -S or --start option) to the end
of the time window (see description of -T or --finish
option). The -O or --origin option allows the
specification of an origin within the time window to be
used as the initial sample time. This is useful for
interactive use of a PCP tool with the pmtime(1) VCR replay
facility.
The origin argument accepted by -O (or --origin) conforms
to the same syntax and semantics as the starttime argument
for the -T (or --finish) option.
For example --origin -0 specifies that the initial position
should be at the end of the time window; this is most
useful when wishing to replay ``backwards'' within the time
window.
The datetime argument for the -O (or --origin), -S (or --start)
and -T (or --finish) options consists of:
date time zone day relative
A date can be one of: YY-MM-DD, MM/DD/YY, DD Month YYYY, or Month
DD YYYY. A time can be one of: HH:MM:SS, HH:MM. HH:MM can use
either the 12 hour (via an am or pm suffix) or 24 hour convention.
A day of the week can be a spelled out day of the week, optionally
preceded by an ordinal number such as second Tuesday. A zone is a
time zone value as specified by the tzselect(8) command. A
relative time can be a time unit that is: preceded by a cardinal
number such as 1 year or 2 months, preceded by one of the time
words this or last, or succeeded by the time word ago. A relative
time can also be one of the time words: yesterday, today,
tomorrow, now. Examples of datetime strings are: 1996-03-04
13:07:47 EST Mon, 1996-03-05 14:07:47 EST -1hour, Mon Mar 4
13:07:47 1996, Mar 4 1996, Mar 4, Mar, 13:07:50 or 13:08.
For any missing low order fields, the default value of 0 is
assumed for hours, minutes and seconds, 1 for day of the month and
Jan for months. Hence, the following are equivalent: --start '@
Mar 1996' and --start '@ Mar 1 00:00:00 1996'.
If any high order fields are missing, they are filled in by
starting with the year, month and day from the current time (real-
time mode) or the time at the beginning of the set of PCP archives
(archive mode) and advancing the time until it matches the fields
that are specified. So, for example if the time window starts by
default at ``Mon Mar 4 13:07:47 1996'', then --start @13:10
corresponds to 13:10:00 on Mon Mar 4, 1996, while --start @10:00
corresponds to 10:00:00 on Tue Mar 5, 1996 (note this is the
following day).
For greater precision than afforded by datetime(3), the seconds
component may be a floating point number.
If a timezone is not included in a datetime then there are several
interpretations available depending on the other command line
options used. The default is to use the local timezone on the
system where the PCP tool is being run. A -Z or --timezone option
specifies an explicit timezone, else a -z or --hostzone option
changes the timezone to the local timezone at the host that is the
source of the performance metrics.
The number of performance metric names supported by PCP on most
platforms ranges from many hundreds to several thousand. The PCP
libraries and applications use an internal identification scheme
that unambiguously associates a single integer with each known
performance metric. This integer is known as the Performance
Metric Identifier, or PMID. Although not a requirement, PMIDs
tend to have global consistency across all systems, so a
particular performance metric usually has the same PMID.
For all users and most applications, direct use of the PMIDs would
be inappropriate (this would limit the range of accessible
metrics, make the code hard to maintain, force the user interface
to be particularly baroque, and so on). Hence a Performance
Metrics Name Space (PMNS) is used to provide external names and a
hierarchic classification for performance metrics. A PMNS is
represented as a tree, with each node having a label, a pointer to
either a PMID (for leaf nodes) or a set of descendent nodes in the
PMNS (for non-leaf nodes).
A node label must begin with an alphabetic character, followed by
zero or more characters drawn from the alphabetics, the digits and
character ``_'' (underscore). For alphabetic characters in a node
label, upper and lower case are distinguished.
By convention, the name of a performance metric is constructed by
concatenation of the node labels on a path through the PMNS from
the root node to a leaf node, with a ``.'' as a separator. The
root node in the PMNS is unlabeled, so all names begin with the
label associated with one of the descendent nodes below the root
node of the PMNS, for example kernel.percpu.syscall. Typically
(although this is not a requirement) there would be at most one
name for each PMID in a PMNS. For example kernel.all.cpu.idle and
disk.dev.read are the unique names for two distinct performance
metrics, each with a unique PMID.
Groups of related PMIDs may be named by naming a non-leaf node in
the PMNS tree, for example disk.
The default local PMNS used by pmcd is located at
$PCP_VAR_DIR/pmns/root however the environment variable
PMNS_DEFAULT may be set to the full pathname of a different PMNS
which will then be used as the default local PMNS.
Most applications do not use the local PMNS directly, but rather
import parts of the PMNS as required from the same place that
performance metrics are fetched, i.e. from pmcd(1) for live
monitoring or from a set of PCP archives for retrospective
monitoring.
To explore the PMNS use pminfo(1), or if the PCP GUI package is
installed the New Chart and Metric Search windows within
pmchart(1).
Some performance metrics have a singular value. For example, the
available memory or number of context switches have one value per
performance metric source, that is, one value per host. The
metric descriptor (metadata) for each metric makes this fact known
to applications that process values for these single-valued
metrics.
Some performance metrics have a set of values or instances in each
implementing performance metric domain. For example, one value
for each disk, one value for each process, one value for each CPU,
or one value for each activation of a given application. When a
metric has multiple instances, the PMNS does not represent this in
metric names; rather, a single metric may have an associated set
of values. Multiple values are associated with the members of an
instance domain, such that each instance has a unique instance
identifier within the associated instance domain. For example,
the ''per CPU´´ instance domain may use the instance identifiers
0, 1, 2, 3, and so on to identify the configured processors in the
system. Internally, instance identifiers are encoded as binary
values, but each performance metric domain also supports
corresponding strings as external names for the instance
identifiers, and these names are used at the user interface to the
PCP utilities.
Multiple performance metrics may be associated with a single
instance domain. For example, per-process metrics under proc all
share the same instance domain.
PCP arranges for information describing instance domains to be
exported from the performance metric domains to the applications
that require this information. Applications may also choose to
retrieve values for all instances of a performance metric, or some
arbitrary subset of the available instances.
Metric names and the instance domain concept provides two-
dimensions for the modelling of performance metrics. This is a
clear and simple model, however on some occasions it does not
suffice. For example, a metric may wish to represent higher
dimensional data such as ``per CPU'' counters for each running
process. In these cases it is common to create a compound
instance, where the name is composed of each component with a
separator in-between (for example, ``87245::cpu7'' might be used
to separate process ID from CPU ID) to create flattened instance
names. Additionally, such cases benefit from the use of metric
instances labels to explicitly show the separate components
(continuing the example from above, labels
``{"pid":87245,"cpu":7}'' might be used).
In configuration files and (to a lesser extent) command line
options, metric specifications adhere to the following syntax
rules by most tools. See the tool specific manual pages for the
exact syntax supported.
If the source of performance metrics is real-time from pmcd(1)
then the accepted syntax is
host:metric[instance1,instance2,...]
If the source of performance metrics is a set of PCP archives then
the accepted syntax is
archive/metric[instance1,instance2,...]
The host:, archive/ and [instance1,instance2,...] components are
all optional.
The , delimiter in the list of instance names may be replaced by
white space.
Special characters in instance names may be escaped by surrounding
the name in double quotes or preceding the character with a
backslash.
White space is ignored everywhere except within a quoted instance
name.
An empty instance is silently ignored, and in particular ``[]'' is
the same as no instance, while ``[one,,,two]'' is parsed as
specifying just the two instances ``one'' and ``two''.
As a special case, if the host is the single character ``@'' then
this refers to a PM_CONTEXT_LOCAL source, see pmNewContext(3).
Since PCP version 3.6.11, a monitor can explicitly request a
secure connection to a collector host running pmcd(1) or
pmproxy(1) using the PM_CTXFLAG_SECURE context flag. If the PCP
Collector host supports this feature - refer to the
pmcd.feature.secure metric for confirmation of this - a TLS/SSL
(Transport Layer Security or Secure Sockets Layer) connection can
be established which uses public key cryptography and related
techniques. These features aim to prevent eavesdropping and data
tampering from a malicious third party, as well as providing
server-side authentication (confident identification of a server
by a client) which can be used to guard against man-in-the-middle
attacks.
A secure pmcd connection requires use of certificate-based
authentication. The security features offered by pmcd and pmproxy
are implemented using the OpenSSL APIs and utilities. The
openssl(1) tool can be used to create certificates suitable for
establishing trust between PCP monitor and collector hosts.
A complete description is beyond the scope of this document, refer
to the PCP ENVIRONMENT, FILES and SEE ALSO sections for detailed
information. This includes links to tutorials on the steps
involved in setting up the available security features.
In the absence of an explicit hostname specification, most tools
will default to the local host in live update mode. In PCP
releases since 3.8.4 onward, this results in an efficient local
protocol being selected - typically a Unix domain socket. If this
option is used (which can also be explicitly requested via the
unix: host specification described below), it is important to note
that all connections will be automatically authenticated. In
other words, the credentials of the user invoking a client tool
will automatically be made available to pmcd(1) and all of its
PMDAs, on the users behalf, such that results can be customized to
the privilege levels of individual users.
Names of remote hosts running the pmcd(1) daemon can of course
also be provided to request a remote host be used. The most basic
form of pmcd host specification is a simple host name, possibly
including the domain name if necessary. However, this can be
extended in a number of ways to further refine attributes of the
connection made to pmcd.
The pmcd port number and also optional pmproxy(1) hostname and its
port number, can be given as part of the host specification, since
PCP version 3.0. These supersede (and override) the old-style
PMCD_PORT, PMPROXY_HOST and PMPROXY_PORT environment variables.
The following are valid hostname specifications that specify
connections to pmcd on host nas1.acme.com with/without a list of
ports, with/without a pmproxy(1) connection through a firewall,
and with IPv6 and IPv4 addresses as shown.
$ pcp --host nas1.acme.com:44321,4321@firewall.acme.com:44322
$ pcp --host nas1.acme.com:44321@firewall.acme.com:44322
$ pcp --host nas1.acme.com:44321@firewall.acme.com
$ pcp --host nas1.acme.com@firewall.acme.com
$ pcp --host nas1.acme.com:44321
$ pcp --host [fe80::2ad2:44ff:fe88:e4f1%p2p1]
$ pcp --host 192.168.0.103
In addition, ``connection attributes'' can also be specified.
These include username, password (can be given interactively and
may depend on the authentication mechanism employed), whether to
target a specific running container, whether to use secure
(encrypted) or native (naked) protocol, and so on. The previous
examples all default to native protocol, and use no
authentication. This can be altered, as in the following
examples.
$ pcp --host pcps://app2.acme.com?container=cae8e6edc0d5
$ pcp --host pcps://nas1.acme.com:44321?username=tanya&method=gssapi
$ pcp --host pcps://nas2.acme.com@firewalls.r.us?method=plain
$ pcp --host pcp://nas3.acme.com
$ pcp --host 192.168.0.103?container=cae8e6edc0d5,method=scram-sha-256
$ pcp --host unix:
$ pcp --host local:
The choice of authentication method, and other resulting
parameters like username, optionally password, etc, depends on the
SASL2 configuration used by each (remote) pmcd. Tutorials are
available specifying various aspects of configuring the
authentication module(s) used, these fine details are outside the
scope of this document.
In all situations, host names can be used interchangeably with
IPv4 or IPv6 addressing (directly), as shown above. In the case
of an IPv6 address, the full address must be enclosed by square
brackets and the scope (interface) must also be specified.
The final local: example above is now the default for most tools.
This connection is an automatically authenticated local host
connection on all platforms that support Unix domain sockets. No
password is required and authentication is automatic. This is
also the most efficient (lowest overhead) communication channel.
The difference between unix: and local: is that the former is a
strict Unix domain socket specification (connection fails if it
cannot connect that way), whereas the latter has a more forgiving
fallback to using localhost (i.e. a regular Inet socket connection
is used when Unix domain socket connections are unavailable).
/etc/pcp.conf
Configuration file for the PCP runtime environment, see
pcp.conf(5).
/etc/pcp/tls.conf
Optionally contains OpenSSL configuration information,
including locations of certificates providing trusted
identification for collector and monitor hosts.
$HOME/.pcp
User-specific directories containing configuration files for
customisation of the various monitor tools, such as
pmchart(1).
$PCP_RC_DIR/pmcd
Script for starting and stopping pmcd(1).
$PCP_PMCDCONF_PATH
Control file for pmcd(1).
$PCP_PMCDOPTIONS_PATH
Command line options passed to pmcd(1) when it is started
from $PCP_RC_DIR/pmcd. All the command line option lines
should start with a hyphen as the first character. This file
can also contain environment variable settings of the form
"VARIABLE=value".
$PCP_BINADM_DIR
Location of PCP utilities for collecting and maintaining PCP
archives, PMDA help text, PMNS files etc.
$PCP_PMDAS_DIR
Parent directory of the installation directory for Dynamic
Shared Object (DSO) PMDAs.
$PCP_RUN_DIR/pmcd.pid
If pmcd is running, this file contains an ascii decimal
representation of its process ID.
$PCP_LOG_DIR/pmcd
Default location of log files for pmcd(1), current directory
for running PMDAs. Archives generated by pmlogger(1) are
generally below $PCP_LOG_DIR/pmlogger.
$PCP_LOG_DIR/pmcd/pmcd.log
Diagnostic and status log for the current running pmcd(1)
process. The first place to look when there are problems
associated with pmcd.
$PCP_LOG_DIR/pmcd/pmcd.log.prev
Diagnostic and status log for the previous pmcd(1) instance.
$PCP_LOG_DIR/NOTICES
Log of pmcd(1) and PMDA starts, stops, additions and
removals.
$PCP_VAR_DIR/config
Contains directories of configuration files for several PCP
tools.
$PCP_SYSCONF_DIR/pmcd/rc.local
Local script for controlling PCP boot, shutdown and restart
actions.
$PCP_VAR_DIR/pmns
Directory containing the set of PMNS files for all installed
PMDAs.
$PCP_VAR_DIR/pmns/root
The ASCII PMNS(5) exported by pmcd(1) by default. This PMNS
is be the super set of all other PMNS files installed in
$PCP_VAR_DIR/pmns.
In addition, if the PCP product is installed the following files
and directories are relevant.
$PCP_LOG_DIR/NOTICES
In addition to the pmcd(1) and PMDA activity, may be used
to log alarms and notices from pmie(1) via pmpost(1).
$PCP_PMLOGGERCONTROL_PATH
Control file for pmlogger(1) instances launched from
$PCP_RC_DIR/pmlogger and/or managed by pmlogger_check(1)
and pmlogger_daily(1) as part of a production PCP archive
collection setup.
In addition to the PCP run-time environment and configuration
variables described in the PCP ENVIRONMENT section below, the
following environment variables apply to all installations.
Note that most uses of these environment variables are optimized
to check the environment only the first time the variable might be
used. As the environment usually is not checked again, the only
safe strategy is to ensure all PCP-related environment variables
are set before the first call into any of the PCP libraries.
PCP_ALLOW_BAD_CERT_DOMAIN
When set, allow clients to accept certificates with
mismatched domain names with no prompt when they are sent
by pmcd or other server components. See
PCP_SECURE_SOCKETS.
PCP_ALLOW_SERVER_SELF_CERT
When set, allow clients to accept self-signed certificates
with no prompt when they are sent by pmcd or other server
components. See PCP_SECURE_SOCKETS.
PCP_CONSOLE
When set, this changes the default console from /dev/tty
(on Unix) or CON: (on Windows) to be the specified console.
The special value of none can be used to indicate no
console is available for use. This is used in places where
console-based tools need to interact with the user, and in
particular is used when authentication is being performed.
PCP_DEBUG
When set, this variable provides an alternate to the -D
command line option described above to initialize the
diagnostic and debug options for applications that use
pmGetOptions(3) to process command line options and
arguments. The value for $PCP_DEBUG is the same as for the
-D command line option, namely a comma-separated list of
debugging option name(s), and/or decimal integers, see
pmdbg(1) for a description of the supported option names
and values.
PCP_DERIVED_CONFIG
When set, this variable defines a colon separated list of
files and/or directories (the syntax is the same as for the
$PATH variable for sh(1)). The components are expanded
into a list of files as follows: if a component of
$PCP_DERIVED_CONFIG is a file, then that file is added to
the list, else if a component is a directory then recursive
descent is used to enumerate all files below that directory
and these are added to the list.
Each file in the resulting list is assumed to contain
definitions of derived metrics as per the syntax described
in pmLoadDerivedConfig(3), and these are loaded in order.
Derived metrics may be used to extend the available metrics
with new (derived) metrics using simple arithmetic
expressions.
If PCP_DERIVED_CONFIG is set, the derived metric
definitions are processed automatically as each new source
of performance metrics is established (i.e. each time a
pmNewContext(3) is called) or when requests are made
against the PMNS.
Any component in the $PCP_DERIVED_CONFIG list or the
expanded list of files that is not a file, or is not a
directory or is not accessible (due to permissions or a bad
symbolic link) will be silently ignored.
PCP_IGNORE_MARK_RECORDS
When PCP archives logs are created there may be temporal
gaps associated with discontinuities in the time series of
logged data, for example when pmcd(1) is restarted or when
multiple archives are concatenated with pmlogextract(1).
These discontinuities are internally noted with a <mark>
record in the PCP archives, and value interpolation as
described in pmSetMode(3) is not supported across <mark>
records (because the values before and after a <mark>
record are not necessarily from a continuous time series).
Sometimes the user knows the data semantics are sound in
the region of the <mark> records, and
$PCP_IGNORE_MARK_RECORDS may be used to suppress the
default behaviour.
If PCP_IGNORE_MARK_RECORDS is set (but has no value) then
all <mark> records will be ignored. Otherwise the value
$PCP_IGNORE_MARK_RECORDS follows the syntax for an interval
argument described above for the -t option, and <mark>
records will be ignored if the time gap between the last
record before the <mark> and the first record after the
<mark> is not more than interval.
PCP_SECURE_SOCKETS
When set, this variable forces any monitor tool connections
to be established using the certificate-based secure
sockets feature. If the connections cannot be established
securely, they will fail.
PCP_TLSCONF_PATH
Specifies the location from which TLS (Transport Layer
Security) configuration settings will be read. These
settings are used by PCP client tools, pmcd and pmproxy
whenever secure (encrypted) communication is requested.
PCP_STDERR
Many PCP tools support the environment variable PCP_STDERR,
which can be used to control where error messages are sent.
When unset, the default behavior is that ``usage'' messages
and option parsing errors are reported on standard error,
other messages after initial startup are sent to the
default destination for the tool, i.e. standard error for
ASCII tools, or a dialog for GUI tools.
If PCP_STDERR is set to the literal value DISPLAY then all
messages will be displayed in a dialog. This is used for
any tools launched from a Desktop environment.
If PCP_STDERR is set to any other value, the value is
assumed to be a filename, and all messages will be written
there.
PMCD_CONNECT_TIMEOUT
When attempting to connect to a remote pmcd(1) on a machine
that is booting, the connection attempt could potentially
block for a long time until the remote machine finishes its
initialization. Most PCP applications and some of the PCP
library routines will abort and return an error if the
connection has not been established after some specified
interval has elapsed. The default interval is 5 seconds.
This may be modified by setting PMCD_CONNECT_TIMEOUT in the
environment to a real number of seconds for the desired
timeout. This is most useful in cases where the remote
host is at the end of a slow network, requiring longer
latencies to establish the connection correctly.
PMCD_RECONNECT_TIMEOUT
When a monitor or client application loses a connection to
a pmcd(1), the connection may be re-established by calling
a service routine in the PCP library. However, attempts to
reconnect are controlled by a back-off strategy to avoid
flooding the network with reconnection requests. By
default, the back-off delays are 5, 10, 20, 40 and 80
seconds for consecutive reconnection requests from a client
(the last delay will be repeated for any further attempts
after the fifth). Setting the environment variable
PMCD_RECONNECT_TIMEOUT to a comma separated list of
positive integers will re-define the back-off delays, for
example setting PMCD_RECONNECT_TIMEOUT to ``1,2'' will
back-off for 1 second, then attempt another connection
request every 2 seconds thereafter.
PMCD_REQUEST_TIMEOUT
For monitor or client applications connected to pmcd(1),
there is a possibility of the application "hanging" on a
request for performance metrics or metadata or help text.
These delays may become severe if the system running pmcd
crashes, or the network connection is lost. By setting the
environment variable PMCD_REQUEST_TIMEOUT to a number of
seconds, requests to pmcd will timeout after this number of
seconds. The default behavior is to be willing to wait 10
seconds for a response from every pmcd for all
applications.
PMCD_WAIT_TIMEOUT
When pmcd(1) is started from $PCP_RC_DIR/pmcd the check on
pmcd's readiness will wait up to PMCD_WAIT_TIMEOUT seconds.
If pmcd has a long startup time (such as on a very large
system), then PMCD_WAIT_TIMEOUT can be set to provide a
maximum wait longer than the default 60 seconds.
PMNS_DEFAULT
If set, then interpreted as the full pathname to be used as
the default local PMNS for pmLoadNameSpace(3). Otherwise,
the default local PMNS is located at
$PCP_VAR_DIR/pcp/pmns/root for base PCP installations.
PCP_COUNTER_WRAP
Many of the performance metrics exported from PCP agents
have the semantics of counter meaning they are expected to
be monotonically increasing. Under some circumstances, one
value of these metrics may smaller than the previously
fetched value. This can happen when a counter of finite
precision overflows, or when the PCP agent has been reset
or restarted, or when the PCP agent is exporting values
from some underlying instrumentation that is subject to
some asynchronous discontinuity.
The environment variable PCP_COUNTER_WRAP may be set to
indicate that all such cases of a decreasing ``counter''
should be treated as a counter overflow, and hence the
values are assumed to have wrapped once in the interval
between consecutive samples. This ``wrapping'' behavior
was the default in earlier PCP versions, but by default has
been disabled in PCP release from version 1.3 on.
PCP_PMDAS_DIR
The PCP_PMDAS_DIR environment variable may be used to
modify the directory used by pmcd(1) and pmNewContext(3)
(for PM_CONTEXT_LOCAL contexts) when searching for a daemon
or DSO PMDA.
PMCD_PORT
The TCP/IP port(s) used by pmcd(1) to create the socket for
incoming connections and requests, was historically 4321
and more recently the officially registered port 44321; in
the current release, both port numbers are used by default
as a transitional arrangement. This may be over-ridden by
setting PMCD_PORT to a different port number, or a comma-
separated list of port numbers. If a non-default port is
used when pmcd is started, then every monitoring
application connecting to that pmcd must also have
PMCD_PORT set in their environment before attempting a
connection.
The following environment variables are relevant to installations
in which pmlogger(1), the PCP archiver, is used.
PMLOGGER_PORT
The environment variable PMLOGGER_PORT may be used to
change the base TCP/IP port number used by pmlogger(1) to
create the socket to which pmlc(1) instances will try and
connect. The default base port number is 4330. When used,
PMLOGGER_PORT should be set in the environment before
pmlogger is executed.
PMLOGGER_REQUEST_TIMEOUT
When pmlc(1) connects to pmlogger(1), there is a remote
possibility of pmlc "hanging" on a request for information
as a consequence of a failure of the network or pmlogger.
By setting the environment variable
PMLOGGER_REQUEST_TIMEOUT to a number of seconds, requests
to pmlogger will timeout after this number of seconds. The
default behavior is to be willing to wait forever for a
response from each request to a pmlogger. When used,
PMLOGGER_REQUEST_TIMEOUT should be set in the environment
before pmlc is executed.
If you have the PCP product installed, then the following
environment variables are relevant to the Performance Metrics
Domain Agents (PMDAs).
PMDA_LOCAL_PROC
Use this variable has been deprecated and it is now
ignored. If the ``proc'' PMDA is configured as a DSO for
use with pmcd(1) on the local host then all of the ``proc''
metrics will be available to applications using a
PM_CONTEXT_LOCAL context.
The previous behaviour was that if this variable was set,
then a context established with the type of
PM_CONTEXT_LOCAL will have access to the ``proc'' PMDA to
retrieve performance metrics about individual processes.
PMDA_LOCAL_SAMPLE
Use this variable has been deprecated and it is now
ignored. If the ``sample'' PMDA is configured as a DSO for
use with pmcd(1) on the local host then all of the
``sample'' metrics will be available to applications using
a PM_CONTEXT_LOCAL context.
The previous behaviour was that if this variable was set,
then a context established with the type of
PM_CONTEXT_LOCAL will have access to the ``sample'' PMDA if
this optional PMDA has been installed locally.
PMIECONF_PATH
If set, pmieconf(1) will form its pmieconf(5) specification
(set of parameterized pmie(1) rules) using all valid
pmieconf files found below each subdirectory in this colon-
separated list of subdirectories. If not set, the default
is $PCP_VAR_DIR/config/pmieconf.
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).
For environment variables affecting PCP tools, see
pmGetOptions(3).
pcp(1), pmcd(1), pmie(1), pmie_daily(1), pminfo(1), pmlc(1),
pmlogger(1), pmlogger_daily(1), pmrep(1), pmstat(1), pmval(1),
systemctl(1), LOGIMPORT(3), LOGARCHIVE(5), pcp.conf(5),
pcp.env(5), PMNS(5) and chkconfig(8).
If the PCP GUI package is installed, then the following entries
are also relevant:
pmchart(1), pmtime(1), and pmdumptext(1).
If the secure sockets extensions have been enabled, then the
following references are also relevant:
https://pcp.io/documentation.html
https://pcp.readthedocs.io/en/latest/QG/EncryptedConnections.html
https://pcp.readthedocs.io/en/latest/QG/AuthenticatedConnections.html
Also refer to the books Performance Co-Pilot User's and
Administrator's Guide and Performance Co-Pilot Programmer's Guide
which can be found at https://pcp.readthedocs.io/en/latest/ .
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 2025-08-11.
(At that time, the date of the most recent commit that was found
in the repository was 2025-08-11.) 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 PCPINTRO(1)
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