|Main index||Section 8||日本語||Options|
The options are as follows:
|Generate output via libxo(3) in a selection of different human and machine readable formats. See xo_parse_args(3) for details on command line arguments.|
When used with
Repeat the display
The first display is for the time since a reboot and each subsequent
report is for the time period since the last display.
If no repeat
is specified, and
|Report on the number fork(2), vfork(2) and rfork(2) system calls since system startup, and the number of pages of virtual memory involved in each.|
|Changes memory columns into more easily human readable form. The default if standard output is a terminal device.|
|Changes memory columns into straight numbers. The default if standard output is not a terminal device (such as a script).|
|Report on the number of interrupts taken by each device since system startup.|
|Extract values associated with the name list from the specified core.|
|Report on the usage of kernel dynamic memory allocated using malloc(9) by type.|
|Change the maximum number of disks to display from the default of 2.|
|Display a list of virtual memory objects in the system and the resident memory used by each object.|
|Report per-cpu system/user/idle cpu statistics.|
Specify which types of devices to display.
There are three different
categories of devices:
|da||Direct Access devices|
|sa||Sequential Access devices|
|worm||Write Once Read Multiple devices|
|Optical Memory devices|
|Medium Changer devices|
|array||Storage Array devices|
|Enclosure Services devices|
|IDE||Integrated Drive Electronics devices|
|SCSI||Small Computer System Interface devices|
|other||Any other device interface|
The user must specify at least one device type, and may specify at most one device type from each category. Multiple device types in a single device type statement must be separated by commas.
Any number of
|Display the contents of the sum structure, giving the total number of several kinds of paging related events which have occurred since system startup.|
|Pause wait seconds between each display. If no repeat wait interval is specified, the default is 1 second. The vmstat command will accept and honor a non-integer number of seconds.|
|Report on memory used by the kernel zone allocator, uma(9), by zone.|
arguments may be given after their respective flags at any point
on the command line before the
argument(s), or without their flags, as the final argument(s).
The latter form is accepted for backwards compatibility, but it is
preferred to use the forms with
By default, vmstat displays the following information:
Information about the number of threads in various states:
|r||running or in run queue|
|b||blocked for resources (i/o, paging, etc.)|
Information about the usage of virtual and real memory.
Mapped virtual memory is a sum of all of the virtual pages belonging to mapped virtual memory objects. Note that the entire memory object's size is considered mapped even if only a subset of the object's pages are currently mapped. This statistic is not related to the active page queue which is used to track real memory.
|avm||mapped virtual memory (previously called active in vmstat output )|
|fre||size of the free list|
Information about page faults and paging activity.
These are given in units per second.
|flt||total number of page faults|
|re||page reclaims (simulating reference bits)|
|pi||pages paged in|
|po||pages paged out|
|sr||pages scanned by page daemon|
Disk operations per second (this field is system dependent).
Typically paging will be split across the available drives.
The header of the field is the first two characters of the disk name and
the unit number.
If more than two disk drives are configured in the system,
displays only the first two drives, unless the user specifies the
Trap/interrupt rates per second.
|in||device interrupts (including clock interrupts)|
|cs||cpu context switches|
Breakdown of percentage usage of CPU time.
|us||user time for normal and low priority processes|
|sy||system and interrupt time|
|default kernel namelist|
|/dev/kmem||default memory file|
vmstat -w 5
will print what the system is doing every five seconds.
vmstat -p da -p cd -w 1
will tell vmstat to select the first two direct access or CDROM devices and display statistics on those devices, as well as other systems statistics every second.
The sections starting with ``Interpreting system activity'' in Installing and Operating 4.3BSD.
|VMSTAT (8)||May 26, 2020|
|Main index||Section 8||日本語||Options|
|“||This philosophy, in the hands of amateurs, leads to inexplicably mind-numbing botches like the existence of two programs, “head” and “tail,” which print the first part or the last part of a file, depending. Even though their operations are duals of one another, “head” and “tail” are different programs, written by different authors, and take different options!||”|
|— The Unix Haters' handbook|