pcp-ss - Man Page

report socket statistics


pcp [pcp options] ss [ss options]


pcp-ss reports socket statistics collected by the pmdasockets(1) PMDA agent. The command is intended to be closely compatible with many of the ss(8) command line options and reporting formats, but also offer the advantages of local or remote monitoring (in live mode) and also historical replay from a previously recorded PCP archive.

Live mode uses the pcp -h host option and requires the pmdasockets(1) PMDA to be installed and enabled on the target host (local or remote), see pmdasockets(1) for details on how to enable the sockets PMDA on a particular host. The default source is live metrics collected on localhost, if neither of the -h or -a options are given.

Historical/archive replay uses the pcp -a archive option, where archive is the basename of a previously recorded PCP archive. The archive replay feature is particularly useful because socket statistics can be reported for a designated time using the pcp --origin option (which defaults to the start time of the archive).


pcp ss

Display default basic socket information for the local host. This includes Netid (tcp, udp, etc), State (ESTAB, TIME_WAIT, etc), Recv-Q and Send-Q queue lengths and the local and peer address and port for each socket.

pcp -h somehost ss -noemitauO

Display the same basic socket information as above for the host somehost, which may be the default localhost. The additional command line arguments (-noemitauO) display one line per socket (-O), numeric (-n) service names (default), timer information (-o), extended socket details (-e), socket memory usage (-m), internal TCP information (-i), both udp (-u) and tcp sockets (-t) and both listening and non-listening sockets (-a).

pcp -a somearchive -S'@Wed 16 Jun 2021 12:57:21' ss -noemitauO

Display the same information as the above example, but for the archive somearchive starting at the given time Wed 16 Jun 2021 12:57:21. Note the literal @ prefix is required for an absolute time, see PCPIntro(1) for details. The archive must of course contain data for the requested time. You can use pmdumplog -l somearchive to examine the time bounds of somearchive.

pcp -a somearchive -O-0 ss -noemitauO

As above, but with an offset of zero seconds (-O-0) before the current end of somearchive, i.e. the most recently logged data. Note that somearchive may be curently growing (i.e. being logged with pmlogger(1)).


Due to the large number of options supported by pcp-ss, the pcp(1) command should always be used to invoke pcp-ss in order to specify options such as the metrics source (host or archive) and also (in archive mode), the requested start time or offset, and timezone using the following options:

-h,  --host

The remote hostname to connect to in live mode

-a,  --archive

The archive file to use for historical sampling

-O,  --origin

The time offset to use within an archive (implies -a)

-S,  --start

The start time (e.g. in ctime(3) format) to use when replaying an archive.

-Z,  --timezone

Use a specific timezone. Since pcp-ss doesn't report timestamps, this only affects the interpretation of an absolute starting time (-S) or offset (-O).

-z,  --hostzone

In archive mode, use the timezone of the archive rather than the timezone on the local machine running pcp-ss. The timezone, start and finish times of the archive may be examined using pmdumplog(1) with the -L option.

The above pcp options become indirectly available to the pcp-ss command via environment variables - refer to PCPIntro(1) for a complete description of these options.

The additional command line options available for pcp-ss itself are:

-h, --help

show help message and exit

-V, --version

output version information

-n, --numeric

don't resolve service names

-r, --resolve

resolve host names

-a, --all

display all sockets

-l, --listening

display listening sockets

-o, --options

show timer information

-e, --extended

show detailed socket information

-m, --memory

show socket memory usage

-p, --processes

show process using socket

-i, --info

show internal TCP information

-s, --summary

show socket usage summary

-b, --bpf

show bpf filter socket information

-E, --events

continually display sockets as they are destroyed

-Z, --context

display process SELinux security contexts

-z, --contexts

display process and socket SELinux security contexts

-N, --net

switch to the specified network namespace name

-4, --ipv4

display only IP version 4 sockets

-6, --ipv6

display only IP version 6 sockets

-0, --packet

display PACKET sockets

-t, --tcp

display only TCP sockets

-M, --mptcp

display only MPTCP sockets

-S, --sctp

display only SCTP sockets

-u, --udp

display only UDP sockets

-d, --dccp

display only DCCP sockets

-w, --raw

display only RAW sockets

-x, --unix

display only Unix domain sockets

-H, --noheader

Suppress header line

-O, --oneline

socket's data printed on a single line


The columns in the pcp-ss report vary according to the command line options and have the same interpretation as described in ss(8).

One difference with pcp-ss is that the first line in the report begins with '# Timestamp' followed by the timestamp (in the requested timezone, see -z and -Z above) of the sample data from the host or archive source. Following the timestamp is the currently active filter string for the metrics source. In archive mode, the active filter can be changed dynamically, even whilst the archive is being recorded. This is different to ss(8) where the filter is optionally specified on the command line of the tool and is always 'live', i.e. ss(8) does not support retrospective replay. With pcp-ss, the filter is stored in the back-end PMDA, see pmdasockets(1), in the metric network.persocket.filter. The default filter is state connected, which can be changed by storing a new string value in the network.persocket.filter metric using pmstore(1), e.g. pmstore network.persocket.filter "state established". This will override the persistent default filter, which is stored in a PMDA configuration file and loaded each time the sockets PMDA is started. See pmdasockets(1) for further details and see ss(8) for details of the filter syntax and examples.

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(5).

For environment variables affecting PCP tools, see pmGetOptions(3).

See Also

PCPIntro(1), pcp(1), pmdasockets(1), pmlogger(1), pcp.conf(5) and ss(8).


PCP Performance Co-Pilot