DNS performance Help when query log is off -- which default parameters will impact the DNS performance

[Paul Kosinski]

Could it be that you're network limited?

In any case, the values of the following parameters may be illuminating
(they may be obtained via "rndc status").

  CPUs found
  worker threads
  UDP listeners per interface

For example, my very lightly loaded authoritative server reports:

  version: BIND 9.10.6 <id:9d1ea0b> (Not currently available)
  boot time: Fri, 12 Jan 2018 23:49:54 GMT
  last configured: Wed, 21 Feb 2018 05:00:02 GMT
  CPUs found: 4
  worker threads: 4
  UDP listeners per interface: 3
  number of zones: 4
  debug level: 0
  xfers running: 0
  xfers deferred: 0
  soa queries in progress: 0
  query logging is ON
  recursive clients: 0/0/1000
  tcp clients: 0/100
  server is up and running

--------------

On Wed, 21 Feb 2018 20:59:16 +0000
"PENG, JUNAN" <jp2111 at att.com> wrote:

> Hi, Tony
> 
> During my performance test,  I also tested the performance without
> query logs.  I disabled the query log feature , but  it seemed that
> QPS  couldn't  go higher (about 75KQPS)  when CPU still had lots of
> room  --  Named CPU Usage was about 250%,  but in theory  it can
> reach to 400% (4 vCPU).
> 
> 
> In your opinion,  which default parameters I need pay attention to ,
> which will impact system capacity performance when query log is off?
> 
> 
> Our Bind version is 9.10.5.  Do you know what version you think will
> have better multi-threading ?
> 
> 
> Thank you very much!
> 
> Michael
> 
> -----Original Message-----
> From: PENG, JUNAN 
> Sent: Wednesday, February 21, 2018 11:32 AM
> To: 'Tony Finch' <dot at dotat.at>
> Subject: RE: Help 
> 
> Another thing:
> 
> When query log is on.
> 
> Traffic is 35k QPS,   the Named CPU usage is 260%
> Traffic is 40K QPS,  the Named CPU usage is 260% Traffic is 50K QPS,
> the Named CPU usage is 260% Traffic is 70 -100 KQPS, the named CPU
> usage is still 260% 
> 
> When the named CPU usage has a limitation 260% here ? (in theory, it
> should be 400%)
> 
> BR
> Michael
> 
> -----Original Message-----
> From: Tony Finch [mailto:dot at dotat.at]
> Sent: Wednesday, February 21, 2018 11:09 AM
> To: PENG, JUNAN <jp2111 at att.com>
> Cc: bind-users at lists.isc.org
> Subject: Re: Help 
> 
> PENG, JUNAN <jp2111 at att.com> wrote:
> >
> > Why Query log off/on  feature is impacting named CPU Usage ?
> 
> It has to serialize query processing in order to write to the log,
> and that serialization barrier limits the parallelism that it can
> achieve (due to Amdahl's law).
> 
> Tony.