[Pdns-users] Recursor QPS ceiling

abang abang at t-ipnet.net
Thu Dec 18 07:19:52 UTC 2014

Hi Ciro,

Tried it quickly with dnsperf (http://nominum.com/measurement-tools/):

# echo -e "localhost.\tA" > datafile
# pdns_recursor --threads=4 --pdns-distributes-queries=no
# dnsperf -c2 -n 10000000 -l 10 -d datafile


  Queries sent:         3314870
  Queries completed:    3314870 (100.00%)
  Queries lost:         0 (0.00%)

  Response codes:       NOERROR 3314870 (100.00%)
  Average packet size:  request 27, response 43
  Run time (s):         10.000025
  Queries per second:   331486.171285

  Average Latency (s):  0.000040 (min 0.000020, max 0.002530)
  Latency StdDev (s):   0.000038

You need a Server with at least 8 cpu cores for this example. Or you can
run dnsperf on a different server.

If you set pdns-distributes-queries=yes, the Recursor uses always the
same thread for one specific query name (localhost. in this example).
This improves the cache-hit-rate and thus the performance for normal


Am 18.12.2014 00:23, schrieb Ciro Iriarte:
> Hi!, could anybody achieve more than 100k QPS on a recursor while
> hitting cache?.
> I only run two tests so far and in both cases the ceiling was around
> 100k QPS. The machine seems to be able to take more beating,  maybe I
> just need more clients or there's some kind of logic limit.
> Any comments?.
> Regards,
> Ciro

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