Hashing, take 2

[Andre Bergei]

> > Hi.
> > 
> > Does this patch speed up the cgi's?
> 
> Slightly, yes, but a different amount on different systems 
> based on the conditions below. The greatest benefit will be 
> for systems that accept a receive a large amount of passive 
> checks though.

You mean it will speed up the processing of passive checks?

> On systems where strlen() isn't a compiler intrinsic it will 
> provide a fairly large boost.
> 
> If you used to have lots of collisions with the additive hash 
> previously used you should see a fairly nice improvement 
> (there's no way of knowing how many collisions you had per 
> bucket without hashing all of your data with both algorithms 
> and comparing it). Typically, networks with a proper 
> naming-standard has many collisions with additive hashes.
> 
> Systems where strcmp() isn't a compiler intrinsic, or where 
> 8-bit operations are terribly expensive, will see a vast 
> improvement, although this depends largely on the condition 
> above as well as the number of elements monitored.
> 
> Systems with a large call overhead will benefit greatly as 
> the hash-functions and some of the hash-comparison functions 
> are inline.
> 
> Systems where the compiler does poor branch-prediction should 
> see some fairly large improvements.
> 
> Very small installations will notice a very slight 
> performance degradation (actually, they won't notice it 
> because pages will appear to load instantaneously anyways).
> > If so i'm willing to take it for a spin and report my findings.
> > 
> 
> Please do. The main issue at hand here is stability at first. 
> If this patch works out well we can start chopping up the 
> code to be better compartmentalized and each section of it 
> can then be optimized to the extremes wrt both resources and 
> speed without having to gamble with stability.

With summer comes spare time, yay :)
I've finally got around to testing this patch, and I think i've found a
bug.
The deamon starts fine, and nagios -v reports 32616 services and 3033
hosts.

But the cgi's do not show all my services.




> 
> As for the GUI, it would need a complete re-design that would 
> also affect the core for it to be noticably faster. Ethan's 
> not willing to do that (I agree with him) since the effort 
> would be wasted once the new GUI emerges.




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