vmstat output

[Chris Torek]

In article <633 at bcsaic.UUCP> phyllis at bcsaic.UUCP writes:
>I'm examining system performance on an Ultrix 1.2 system.  The output 
>from 'vmstat' includes 'active virtual pages' (avm) and 'free pages'
>(fre).  Can someone explain to me how to interpret this information?  

`Active virtual memory' is the sum of the virtual sizes of all
`active' processes.  Here an active process is defined as one that
is running, waiting for `fast' I/O (e.g., disk read), or asleep
but not for more than twenty seconds.  `Free pages' are those pages
that are not allocated to any process.  The machine begins paging
whenever free space gets low enough (`low enough' depends on your
configuration, and on any kernel fixes you may have installed).
The `sweep rate' (sr) goes up, and page outs (po) and reclaims (re)
begin to occur.  If the deficit (de) becomes nonzero the machine
is `desperate' for real memory.  If the paging rate is `high enough',
or the system is `desperate', it will begin swapping.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 1516)
UUCP:	seismo!umcp-cs!chris
CSNet:	chris at umcp-cs		ARPA:	chris at mimsy.umd.edu