Performance issues with deadwood

[Juergen Daubert]

Hi Sam,

reading in your blog that some test with deadwood might be helpful, 
I took the opportunity to do a simple comparison with unbound [1],
IMHO the best recursive resolver currently available. 

The test I've done is very simple, it just records the time to 
resolve around 100 host-names, see [2] for the list.

Using this list I've done the following after a fresh restart of the 
deadwood resp. unbound resolver:

$:> time $(for h in $(cat hosts.txt); do printf "\n\n\n"; dig $h; done > test.log)

The result is rather disappointing, the mean value over several runs 
is around 
  
  8 min for deadwood and 
  1 min for unbound. 
  
Note that there are several out-timed queries for deadwood but not 
for unbound. See [3] for the log of deadwood, [4] the one of unbound.

If I've repeated the test _without_ restarting deadwood, we have less
timeouts in the second run, the third run is finally clean.

Unbound is not optimized for performance it has all kind of dnssec 
stuff enabled, without the query time is around 12 sec lower.


Some system infos:
CRUX linux system with glibc 2.10.1, deadwood compiled with gcc 4.4.4 
without ipv6 support. 
Deadwood 2.9.06 and H-20100905-2 without any noticeable difference.
Unbound 1.4.6.

Deadwood config:
$:> grep -Ev '^#|^$' /etc/deadwoodrc
bind_address="127.0.0.2"
chroot_dir = "/var/lib/deadwood"
maximum_cache_elements = 10000
recursive_acl = "127.0.0.1/16" 


The above is for sure not very scientifically, but it represents the
feeling I have while browsing with the two resolvers, in respect
of performance and timeouts, and shows that deadwood has problems
resolving some host names immediately. 


hope this helps and best regards
Juergen

[1] http://www.unbound.net/
[2] http://jue.li/tmp/deadwood/hosts.txt
[3] http://jue.li/tmp/deadwood/deadwood-H-20100905-2.log
[4] http://jue.li/tmp/deadwood/unbound-1.4.6.log

-- 
Juergen Daubert  |  mailto:jue at jue.li  
Korb, Germany    |  http://jue.li/crux