pcp-free - 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
- Total installed memory (MemTotal and SwapTotal in /proc/meminfo)
- used
- Used memory (calculated as total - free - buffers -
cache)
- free
- Unused memory (MemFree and SwapFree in /proc/meminfo)
- shared
- Memory used (mostly) by tmpfs (Shmem in /proc/meminfo)
- buffers
- Memory used by kernel buffers (Buffers in /proc/meminfo)
- cache
- Memory used by the page cache and slabs (Cached and SReclaimable in
/proc/meminfo)
- buff/cache
- Sum of buffers and cache
- available
- 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
- 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
- Display detailed low and high memory statistics.
- -m,
--megabytes
- Display the amount of memory in megabytes.
- -o
- 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
- 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.
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).