System Administration Guide, Volume 2

Displaying Virtual Memory Statistics (`vmstat`)

You can use the vmstat command to report virtual memory statistics and such information about system events as CPU load, paging, number of context switches, device interrupts, and system calls. The vmstat command can also display statistics on swapping, cache flushing, and interrupts.

Refer to vmstat(1M) for a more detailed description of this command.

How to Display Virtual Memory Statistics (`vmstat`)

Collect virtual memory statistics using the vmstat command with a time interval.

$ vmstat n

`n`	Interval in seconds between reports.

The table below describes the fields in the vmstat output.

Table 36-1 Output From the vmstat Command


Category	Field Name	Description
`procs`		Reports the following states:
	`r`	The number of kernel threads in the dispatch queue
	`b`	Blocked kernel threads waiting for resources
	`w`	Swapped out LWPs waiting for processing resources to finish
`memory`		Reports on usage of real and virtual memory:
	`swap`	Available swap space
	`free`	Size of the free list
`page`		Reports on page faults and paging activity, in units per second:
	`re`	Pages reclaimed
	`mf`	Minor and major faults
	`pi`	Kbytes paged in
	`po`	Kbytes paged out
	`fr`	Kbytes freed
	`de`	Anticipated memory needed by recently swapped-in processes
	`sr`	Pages scanned by page daemon (not currently in use). If `sr` does not equal zero, the page daemon has been running.
`disk`		Reports the number of disk operations per second, showing data on up to four disks
`faults`		Reports the trap/interrupt rates (per second):
	`in`	Interrupts per second
	`sy`	System calls per second
	`cs`	CPU context switch rate
`cpu`		Reports on the use of CPU time:
	`us`	User time
	`sy`	System time
	`id`	Idle time

Example--Displaying Virtual Memory Statistics

The following example shows the vmstat display of statistics gathered at five-second intervals.

$ vmstat 5
 procs    memory            page             disk      faults     cpu
r b w  swap free re  mf  pi  po  fr de sr f0 s3 -- --  in  sy  cs us sy  id
0 0 8 28312  668  0   9   2   0   1  0  0  0  1  0  0  10  61  82  1  2  97
0 0 3 31940  248  0  10  20   0  26  0 27  0  4  0  0  53 189 191  6  6  88
0 0 3 32080  288  3  19  49   6  26  0 15  0  9  0  0  75 415 277  6 15  79
0 0 3 32080  256  0  26  20   6  21  0 12  1  6  0  0 163 110 138  1  3  96
0 1 3 32060  256  3  45  52  28  61  0 27  5 12  0  0 195 191 223  7 11  82
0 0 3 32056  260  0   1   0   0   0  0  0  0  0  0  0   4  52  84  0  1  99

How to Display System Event Information (`vmstat -s`)

Run vmstat -s to show the total of various system events that have taken place since the system was last booted.

$ vmstat -s
        0 swap ins
        0 swap outs
        0 pages swapped in
        0 pages swapped out
   392182 total address trans. faults taken
    20419 page ins
      923 page outs
    30072 pages paged in
     9194 pages paged out
    65167 total reclaims
    65157 reclaims from free list
        0 micro (hat) faults
   392182 minor (as) faults
    19383 major faults
    85775 copy-on-write faults
    66637 zero fill page faults
    46309 pages examined by the clock daemon
        6 revolutions of the clock hand
    15578 pages freed by the clock daemon
     4398 forks
      352 vforks
     4267 execs
 12926285 cpu context switches
109029866 device interrupts
   499296 traps
 22461261 system calls
   778068 total name lookups (cache hits 97%)
    18739 user   cpu
    34662 system cpu
 52051435 idle   cpu
    25252 wait   cpu

How to Display Swapping Statistics (`vmstat -S`)

Run vmstat -S to show swapping statistics.

$ vmstat -S
 procs     memory            page            disk          faults      cpu
 r b w   swap  free  si  so pi po fr de sr f0 s0 s6 --   in   sy   cs us sy id
 0 0 0 200968 17936   0   0  0  0  0  0  0  0  0  0  0  109   43   24  0  0 100

The fields are described in the table below.

Table 36-2 Output From the vmstat -S Command


Field Name	Description
`si`	Average number of LWPs swapped in per second
`so`	Number of whole processes swapped out

Note -

The vmstat command truncates the output of both of these fields. Use the sar command to display a more accurate accounting of swap statistics.

How to Display Cache Flushing Statistics (`vmstat -c`)

Run vmstat -c to show cache flushing statistics for a virtual cache.

$ vmstat -c
usr     ctx     rgn     seg     pag     par
  0   60714       5  134584 4486560 4718054

It shows the total number of cache flushes since the last boot. The cache types are described in the table below.

Table 36-3 Output From the vmstat -c Command


Cache Name	Cache Type
`usr`	User
`ctx`	Context
`rgn`	Region
`seg`	Segment
`pag`	Page
`par`	Partial-page

How to Display Interrupts Per Device (`vmstat -i`)

Run vmstat -i to show interrupts per device.

$ vmstat -i

Example--Displaying Interrupts Per Device

The following example shows output from the vmstat -i command.

$ vmstat -i
interrupt         total     rate
--------------------------------
clock          52163269      100
esp0            2600077        4
zsc0              25341        0
zsc1              48917        0
cgsixc0             459        0
lec0             400882        0
fdc0                 14        0
bppc0                 0        0
audiocs0              0        0
--------------------------------
Total          55238959      105

Displaying Virtual Memory Statistics (vmstat)

How to Display Virtual Memory Statistics (vmstat)

Example--Displaying Virtual Memory Statistics

How to Display System Event Information (vmstat -s)

How to Display Swapping Statistics (vmstat -S)

How to Display Cache Flushing Statistics (vmstat -c)