vmstat \- report virtual memory statistics
delves into the system and reports certain statistics kept about
process, virtual memory, disk and cpu activity.
argument, it reports on the number of
since system startup and the number of pages of virtual memory involved in each
argument, it prints the contents
structure, given the total number of several kinds of paging related
events which have occurred since boot.
If none of these options are given,
will report in a (usually) iterative fashion on the virtual memory
In this case, the optional
``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.
is given, the statistics are repeated
Procs: information about numbers of processes in various states.
DW sleeping on short event (disk wait)
SL sleeping for short time, and in main memory
SW runnable or sleeping for a short time, but swapped out
Virtual: information about the state of virtual memory in the system.
TX percentage of active pages which were shared text pages
Real: information about the state of real memory in the system.
USE page frames in use for data+text+stack of active processes
TX percentage of USE which is text (shared program) pages
FRE size of the free list
Fault: 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)
PO dirty page write back rate (pages per second)
FR rate at which free list is replenished (pages per second)
SR scan rate: pageout daemon rpm (this is in revs/minute)
Swp: information about the activity of the swap daemon (process 0).
I process swap in rate (processes per 10 seconds)
O process swap out rate (processes per 10 seconds)
Disk: operations per second (this field is system dependent).
RP /usr (user) file transactions and root file activity
RM paging and /tmp (temporary) file activity
Cpu: cpu context switch rate and breakdown of cpu
usage by percentage in last few seconds.
CS cpu context switch rate in switches per second
Any time not accounted for by US+SY+ID is given to low priority jobs.
The section on configuration in
.I "Setting up the Virtual Memory Extensions to the UNIX System"
by O. Babaoglu and W. Joy
William Joy and Ozalp Babaoglu
So many numbers print out that its sometimes hard to figure out what to watch.