Is maximum swap usage tunable?

[Mark Millard]

On 2018-Mar-4, at 11:51 AM, Mark Millard <marklmi26-fbsd at yahoo.com> wrote:

> 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.)

I was interrupted and screwed up the calculation
text without noticing:

(s/(1000ms))*(ms/w) != 1/(w/s)

> 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)


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