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pcp-free - Man Page

report on free and used memory in the system


pcp [pcp options] free [-bkmgroltVw?] [-c count] [-s interval]


pcp-free gives a summary display of the total amount of free and used physical memory and swap in the system, as well as the caches used by the kernel.

When invoked via the pcp(1) command, the -h/--host, -a/--archive, -O/--origin, -s/--samples, -t/--interval, -Z/--timezone and several other pcp options become indirectly available, see PCPIntro(1) for their descriptions.

The displayed columns are:


Total installed memory (MemTotal and SwapTotal in /proc/meminfo)


Used memory (calculated as total - free - buffers - cache)


Unused memory (MemFree and SwapFree in /proc/meminfo)


Memory used (mostly) by tmpfs (Shmem in /proc/meminfo)


Memory used by kernel buffers (Buffers in /proc/meminfo)


Memory used by the page cache and slabs (Cached and SReclaimable in /proc/meminfo)


Sum of buffers and cache


Estimation of how much memory is available for starting new applications, without swapping. Unlike the data provided by the cache or free fields, this field takes into account page cache and also that not all reclaimable memory slabs will be reclaimed due to items being in use (MemAvailable in /proc/meminfo).


The available command line options are:

-b,  --bytes

Display the amount of memory in bytes.

-c count, --samples=count, --count=count

Terminate the display after count iterations. See also -s.

-g,  --gigabytes

Display the amount of memory in gigabytes.

-k,  --kilobytes

Display the amount of memory in kilobytes. This is the default.

-l,  --lohi

Display detailed low and high memory statistics.

-m,  --megabytes

Display the amount of memory in megabytes.


Disable the display of a "buffer adjusted" line. If the -o option is not specified, free subtracts buffer memory from the used memory and adds it to the free memory reported.

-r,  --terabytes

Display the amount of memory in terabytes.

-s delay, --interval=delay, --seconds=delay

Activate continuous polling delay seconds apart. You may specify any floating point number for delay, or indeed any valid pmParseInterval(3) specification, which includes microsecond resolution delay times. This can be used in conjunction with the -c option.

-t,  --total

Display a line containing the totals.

-V,  --version

Display version number and exit.

-w,  --wide

Switch to the wide mode. The wide mode produces lines longer than 80 characters. In this mode buffers and cache are reported in two separate columns.

-?,  --help

Display usage message and exit.


pcp-free is inspired by the free(1) command and aims to be command line and output compatible with it.

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), free(1), pmParseInterval(3) and environ(7).

Referenced By


PCP Performance Co-Pilot