vmstat.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

.TH vmstat 1
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.SH Name
vmstat \- report virtual memory statistics
.SH Syntax
.B vmstat
[
.I interval
[
.I count
] ] 
.br
.B vmstat \-v
[
.I interval
[
.I count
] ] 
.br
.B vmstat \-fKSsz
.br
.B vmstat \-Kks
.I namelist
[
.I corefile
]
.SH Description
.NXR "vmstat command"
.NXA "vmstat command" "netstat command"
.NXA "vmstat command" "iostat command"
.NXR "virtual memory" "reporting statistics"
.NXR "system" "reporting statistics"
.NXR "memory" "reporting statistics"
The
.PN vmstat
command reports statistics on processes, virtual memory, disk, trap, 
and cpu activity.  
.PP
If 
.PN vmstat
is specified without arguments, this command summarizes the virtual
memory activity since the system was last booted.  If the
.I interval
argument is specified, then successive lines are summaries of activity
over the last
.I interval
seconds.
Because many statistics are sampled in the system every five seconds,
five is a good specification for 
.I interval; 
other statistics vary every second.
If the 
.I count
argument is provided, the statistics are repeated 
.I count
times.  
.PP
When you run
.PN vmstat
the format fields are as follows:
.NXR "vmstat command" "format fields"
.PP
Procs: information about numbers of processes in various states.
.NXR "process" "reporting statistics"
.RS 5
.IP \fBr\fR 5
in run queue
.IP \fBb\fR
blocked for resources (i/o, paging, and so on.)
.IP \fBw\fR
runnable or short sleeper (< 20 seconds) but swapped
.RE
.PP
faults:  trap/interrupt rate averages per second over the last 
5 seconds.
.RS 5
.IP in 5
(non clock) device interrupts per second
.IP sy
system calls per second
.IP cs
cpu context switch rate (switches/second)
.RE
.PP
cpu:  breakdown of percentage usage of cpu time
.RS 5
.IP us 5
user time for normal and low priority processes
.IP sy
system time
.IP id
cpu idle time
.RE
.PP
Memory:  information about the use 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.
.RS 5
.IP \fBavm\fR 5
active virtual pages
.IP \fBfre\fR
size of the free list
.RE
.PP
Pages are reported in units of 1024 bytes.
.PP
If the number of pages exceeds 9999, it is shown in a scaled
representation.  The suffix k indicates multiplication
by 1000 and the suffix m indicates multiplication by
1000000.  For example, the value 12345 appears as 12k.
.PP
page: information about page faults and paging activity.
These are averaged every five seconds, and given in units per second.
The size of a unit is always 1024 bytes and is independent of
the actual page size on a machine.
.NXR "page" "reporting statistics"
.RS 5
.IP \fBre\fR 5
page reclaims (simulating reference bits)
.IP \fBat\fR
pages attached (found in free list not swapdev or filesystem)
.IP \fBpi\fR
pages paged in
.IP \fBpo\fR
pages paged out
.IP \fBfr\fR
pages freed per second
.IP \fBde\fR 
anticipated short term memory shortfall
.IP \fBsr\fR
pages scanned by clock algorithm, per-second
.RE
.PP
disk:  s0, s1 ...sn: Paging/swapping disk sector transfers 
per second (this field is system dependent).
.NXR "disk" "reporting statistics
Typically paging is split across several of the available drives.
This will print for each paging/swapping device configured 
into the kernel.
.SH Options
.IP \fB\-f\fR
Provides reports on the number of
.I forks
and
.I vforks
since system startup and the number of pages of 
virtual memory involved in each
kind of fork.
.IP \fB\-K\fR
Displays usage statistics of the kernel memory allocator.
.IP \fB\-k\fR
Allows a dump to be interrogated to print the contents of the sum 
structure when specified with a 
.I namelist
and
.I corefile.
This is the default.
.IP \fB\-S\fR
Replaces the page reclaim (re) and pages attached (at) fields with
processes swapped in (si) and processes swapped out (so).
.IP \fB\-s\fR
Prints the contents of the
.I sum
structure, giving the total number of several
kinds of paging related
events that have occurred since boot.
.IP \-v
Prints an expanded form of the virtual memory statistics.
.IP \fB\-z\fR
Zeroes out the sum structure if the UID indicates root privilege.
.NXR "fork" "reporting"
.NXR "vfork" "reporting"
.SH Examples
.PP
The following command prints what the system
is doing every five seconds:
.EX
vmstat 5
.EE
To find the status after a core dump use the following:
.EX
cd /usr/adm/crash
vmstat \-k vmunix.? vmcore.?
.EE
.SH Files
.TP 12
.PN /dev/kmem
Kernel memory
.TP
.PN /vmunix
System namelist