4BSD/usr/man/cat1/vmstat.1
VMSTAT(1) UNIX Programmer's Manual VMSTAT(1)
NAME
vmstat - report virtual memory statistics
SYNOPSIS
vmstat [ -fs ] [ -i ] [ interval [ count ] ]
DESCRIPTION
_V_m_s_t_a_t delves into the system and normally reports certain
statistics kept about process, virtual memory, disk, trap
and cpu activity. If given a -f argument, it instead
reports on the number of _f_o_r_k_s and _v_f_o_r_k_s since system
startup and the number of pages of virtual memory involved
in each kind of fork. If given a -s argument, it instead
prints the contents of the _s_u_m structure, giving the total
number of several kinds of paging related events which have
occurred since boot.
If none of these options are given, _v_m_s_t_a_t will report in a
(usually) iterative fashion on the virtual memory activity
in the system. In this case, the optional _i_n_t_e_r_v_a_l argument
causes _v_m_s_t_a_t to report once each _i_n_t_e_r_v_a_l seconds; ``vmstat
5'' will print what the system is doing every five seconds;
this is a good choice of printing interval since this is how
often the statistics are sampled in the system. If a _c_o_u_n_t
is given, the statistics are repeated _c_o_u_n_t times. There
are two formats; fields for the older format which is forced
by the -i option are tersely described later. The default
format fields are:
Procs: information about numbers of processes in various
states.
R in run queue
B blocked for resources (i/o, paging, etc.)
W runnable or short sleeper (< 20 secs) but swapped
Memory: information about the usage of virtual and real
memory. Virtual pages are considered active if they belong
to processes which are running or have run in the last 20
seconds. A ``page'' here is 1024 bytes.
AVM active virtual pages
FRE size of the free list
Page: information about page faults and paging activity.
These are averaged each five seconds, and given in units per
second.
RE page reclaims (simulating reference bits)
PI page-in events
PO page-out events
FR pages freed per second
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VMSTAT(1) UNIX Programmer's Manual VMSTAT(1)
DE anticipated short term memory shortfall
SR scan rate: pageout daemon rpm
Swap: information about the activity of the swap daemon
(process 0).
I process swap ins in last 5 seconds
O process swap outs in last 5 seconds
Disk: operations per second (this field is system depen-
dent). Typically paging will be split across several of the
available drives.
D0 disk 0; on csvax: /usr file system
D1 disk 1; on csvax: on csvax: /va, /tmp and some paging
D2 disk 2; on csvax: /, /vb, /3bsd, /3bsd/usr and some paging
D3 disk 3; on csvax: /arch, /4bsd, /4bsd/usr and some paging
Faults: trap/interrupt rate averages per second over last 5
seconds.
IN (non clock) device interrupts per second
SY system calls per second
PD pseudo-dma interrupts on DZ
CS cpu context switch rate (switches/sec)
Cpu: breakdown of percentage usage of CPU time
US user time for normal and low priority processes
SY system time
ID cpu idle
For the older format, process states are broken down into RU
(runnable), DW (disk i/o wait), PW (page wait), SL (sleeping
in core), and SW (swapped out while recently active). For
memory usage, the percentage of memory used by sharable
pages is printed as TX. Fault information is not printed,
but the percentage of CPU time given to low priority jobs is
given as NI.
FILES
/dev/kmem, /vmunix
SEE ALSO
The sections starting with ``Interpreting system activity''
in _S_e_t_t_i_n_g _u_p _t_h_e _F_o_u_r_t_h _B_e_r_k_e_l_e_y _S_o_f_t_w_a_r_e _T_a_p_e by W. Joy,
O. Babaoglu, and K. Sklower
AUTHORS
William Joy and Ozalp Babaoglu
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BUGS
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