Maintained by: NLnet Labs

[Unbound-users] Requestlist size difference 1.3.4 / 1.4.6

Bagári Péter
Thu Sep 9 11:22:59 CEST 2010


Hi,

I have attached four graphs with the result of a test I have made today.
I have sent continuously increasing amount (max 4000) of DNS queries
for 10 minutes with the "resperf" tool, 3 times, running 2 different
Unbound binaries.
The resperf tool has used a long list of DNS queries collected from
our subscriber traffic recently.

Results on the graph:

1. - 1.4.6 and python module enabled in the config (a small python
script has modified the results of approx 1% of the queries).
2. - 1.4.6 without pythonmod
3. - 1.3.4 (also without pythonmod)

As you can see there is a significant difference in the request list
size and in the removal time of the old entries in the 2nd and 3rd
case.

Can anybody explain it to me what is the reason of this difference?
Is there any possibility to influence the requestlist processing in
the config?

Thanks, Peter


On Wed, Sep 8, 2010 at 2:12 PM, Bagári Péter <bagarip at gmail.com> wrote:
> Hi,
>
> I would like to upgrade our unbound servers from 1.3.4 to 1.4.6. We
> are currently running the service on dual-core Opteron (2 processors)
> linux servers with 16 Gb RAM, peak query rate is 3500 qps per server.
> For the live testing with both versions unbound was recompiled with
> libev3.9 and python module(not enabled in the config currently). Four
> threads are used, outgoing-range and num-queries-per-thread are set to
> 3072, cache sizes are set to 400/800m.
>
> With the 1.3.4 version during the busy hour the request list contains
> 120 entries in average, with a variance of 80-180 roughly. In the
> early hours it goes down to 20 (10-30).
> After the change to the new 1.4.6 version, the size of the requestlist
> has increased, it is at least 2 times higher, but occasionally it goes
> up to 500-600 continuously for 1-2 hours, with higher (1500) peaks.
> Only the running unbound binary has changed on the test system, apart
> from this everything is the same on the server in both cases. Also the
> values of the other performance counters stayed on the same level (CPU
> usage, recursion times, DNS query counters and so on)
>
> I would like to know the reason of this difference between the two
> software versions. I have looked through the release notes, but I
> cannot obviously decide whether or not it is only a symptom of one of
> the software changes.
>
> Thanks for your help,
>
> Peter
>
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