Patchs proposal

[nap]

On Sat, May 16, 2009 at 11:50 AM, Andreas Ericsson <ae at op5.se> wrote:
> nap wrote:
>> This is for the circular host check. I use bit 1->5 of
>> host->is_being_freshened. I'm doing now the hostgroup's service patch.
>>
>
> Thanks a lot! I've mangled the implementation a bit, using macros for
> the most part and accessing host->circular_path_checked instead of
> the higher order bits of is_being_freshened. Since it's now using
> macros, we could re-use this for host- and service dependencies too,
> as those also have the circular_path_checked variable.
Yes, the same algorithm can be use. :)

>
> Timing values from a config with 151109 hosts:
> Patched
> 6.28user 0.19system 0:06.58elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (0major+65723minor)pagefaults 0swaps
>
> Unpatched
> Ctrl-C before it was finished, providing these numbers:
> 3221.77user 0.31system 53:56.51elapsed 99%CPU (0text+0data 0max)k
> 0inputs+0outputs (0major+67480minor)pagefaults 0swaps
>
> So far, your patch provides a speedup of *at least* 51302%. Very nice
> indeed.
Thanks,

>
> With a more modest configuration (15000 hosts), Nagios patched with your
> DFS code completes in 0.72 seconds, while vanilla Nagios needs 3m 33s to
> verify it. In short; Your patch cuts configuration verification down to
> 0.3% of what it originally required. I suspect we can get rid of the
> pre-cache thing entirely now. The speedups it provides are really no
> longer enough to warrant the complexities it entails.
>
> I've also verified with some very strange configurations that it doesn't
> ever miss a circular path chain, and it also prints all elements of a
> circular path even if that chain in itself contains a circular chain.
>
> Consider this:
> host1 parents: host2
> host2 parents: host1,host3
> host3 parents: host1
>
> With your patch, all three hosts are printed (as they should). With
> vanilla Nagios, only host1 and host2 are printed. I simplified this
> example a bit, since I just added random circular paths to a customer's
> config when I was testing it out, but it seems your patch is more
> correct while at the same time scaling linearly with the number of
> hosts. Thanks indeed.
>
Maybe we can take part of my very first email for this patch for the
documentation. I wrote how the patch is working (with the differents
state, etc).

Is the patch ok for the next Nagios version?


Gabès jean

> --
> Andreas Ericsson                   andreas.ericsson at op5.se
> OP5 AB                             www.op5.se
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