How is latency calculated?

[Andreas Ericsson]

Steven D. Morrey wrote:
> Hello Everyone,
> 
> I've been working on updating a Neb Module and bringing it up to compatibility with Nagios 2.12 with an eye towards getting updated to 3x.
> I've run into a bit of a snag though.
> 
> It appears that service check latency climbs along a steady and continual curve.  This curve can be exaggerated by having the module immediately return with fake results.
> For instance under normal circumstances service check latency starts out at about 30 seconds (there are some 27,000 checks being run), this latency will continually grow in a relatively smooth curve at a rate of about 2 secs per hr.
> However if I modify the Neb module to immediately return ok, instead of decreasing service check latency it actually increases it, so instead of 2 secs per hr of growth, it skyrockets to 200 seconds per hr.
> 
> I just can't see how this could be possible.  One would tend to think that having it return immediately, thereby short circuiting the check, that latency should drop to around 0.
> Instead it appears that latency grows as the number of checks completed increases.
> 

That is indeed weird. What happens if you don't load the module at all? Skyrocket or
slow-but-steady increase?

> To top it off, I've grepped the source numerous times to try and find the service check latency calculation and I'm not seeing anything, at least not in the reaper which is where I would expect to find that calculation.
> 
> Can anyone give me some advice here?  Especially if I could know where the latency, both for the individual service check itself as well as average service check latency for the system is being calculated, I would very much appreciate it.

I'll look it up tomorrow. Office-time is officially over in sweden now,
and I'm heading home.

-- 
Andreas Ericsson                   andreas.ericsson at op5.se
OP5 AB                             www.op5.se
Tel: +46 8-230225                  Fax: +46 8-230231

Considering the successes of the wars on alcohol, poverty, drugs and
terror, I think we should give some serious thought to declaring war
on peace.

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