Is maximum swap usage tunable?

[Mark Millard]

bob prohaska fbsd at www.zefox.net write on
Sun Mar 4 18:28:36 UTC 2018:

> The worst-case events were
> dT: 10.002s  w: 10.000s
>  L(q)  ops/s    r/s   kBps   ms/r    w/s   kBps   ms/w   %busy Name
> . . .
>     0      1      0     13    5.6      1     28   5674   88.3  da0b
> . . .

I'll note that (1000s/ms)*(ms/w) != 1/(w/s) here
(and frequently). (ms/r and r/s are similarly related.)

It appears that ms/w counts time with the write
waiting in a queue to be executed or some such but
w/s is strictly the observed rate of writes happening,
independent of how long each waited. (The columns need
not refer to the exact same time frame either as far
as I can tell.)

[Someone may know the actual details of what ms/w
and ms/r spans. The above includes guess work.]

Also: 5674 ms/w is over 5 seconds "per write" (probably
a "mean" form of average, but possibly only one write
covered). I doubt that we can be sure of much about the
stages involved in that large figure if "time waiting
in the queue" and later stages of the processing all
contribute.


===
Mark Millard
marklmi at yahoo.com
( markmi at dsl-only.net is
going away in 2018-Feb, late)