VMSTAT(8) NetBSD System Manager's Manual VMSTAT(8)
NAME
vmstat - report virtual memory statistics
SYNOPSIS
vmstat [-Hefilmsv] [-M core] [-N system] [-c count] [-h histname] [-w wait] [disks]
DESCRIPTION
vmstat reports certain kernel statistics kept about process, virtual mem- ory, disk, trap and cpu activity. The options are as follows: -H Dump all UVM histories. -M core Extract values associated with the name list from the specified core instead of the default /dev/mem. -N system Extract the name list from the specified system instead of the default /netbsd. -c count Repeat the display count times. 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 wait interval is specified, the default is 1 second. -e Report the values of system event counters. -f Report fork statistics. -h histname Dump the specified UVM history. -i Report the values of system interrupt counters. -l List the UVM histories being maintained by the kernel. -m Report on the usage of kernel dynamic memory listed first by size of allocation and then by type of usage. -s Display the contents of the sum structure, giving the total num- ber of several kinds of paging related events which have occurred since system startup. -v Print more verbose information. When used with the -i or -e op- tions, prints out all interrupts or event counters, not just those with non-zero values. -w wait Pause wait seconds between each display. If no repeat count is specified, the default is infinity. By default, vmstat displays the following information: procs Information about the 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 (reported in units of 1024 bytes) are considered active if they belong to processes which are running or have run in the last 20 seconds. avm active virtual pages fre size of the free list page Information about page faults and paging activity. These are av- eraged each five seconds, and given in units per second. flt total page faults re page reclaims (simulating reference bits) pi pages paged in po pages paged out fr pages freed per second sr pages scanned by clock algorithm, per-second disks Disk transfers per second. Typically paging will be split across the available drives. The header of the field is the first char- acter of the disk name and the unit number. If more than four disk drives are configured in the system, vmstat displays only the first four drives. To force vmstat to display specific drives, their names may be supplied on the command line. faults Trap/interrupt rate averages per second over last 5 seconds. in device interrupts per interval (including clock interrupts) sy system calls per interval cs cpu context switch rate (switches/interval) cpu Breakdown of percentage usage of CPU time. us user time for normal and low priority processes sy system time id cpu idle
EXAMPLES
The command ``vmstat -w 5'' will print what the system is doing every five seconds; this is a good choice of printing interval since this is how often some of the statistics are sampled in the system. Others vary every second and running the output for a while will make it apparent which are recomputed every second.
FILES
/netbsd default kernel namelist /dev/mem default memory file
SEE ALSO
fstat(1), netstat(1), nfsstat(1), ps(1), systat(1), iostat(8), pstat(8) The sections starting with ``Interpreting system activity'' in Installing and Operating 4.3BSD.
BUGS
The -c and -w options are only available with the default output. The -H, -h, and -l options are useful only if the system was compiled with support for UVM history. NetBSD 1.5.1 Feburary 12, 1998 2
Powered by man-cgi (2024-08-26). Maintained for NetBSD by Kimmo Suominen. Based on man-cgi by Panagiotis Christias.