Maintained by: NLnet Labs

[Unbound-users] ~10% performance increase in worker_handle_request()

Over Dexia
Tue Jan 7 12:49:32 CET 2014


Am 06.01.2014 17:18, schrieb W.C.A. Wijngaards:
> Hi Robert,
> 
> On 12/29/2013 08:41 PM, Robert Edmonds wrote:
>> Making the local_zone lookup occur after the cache lookup has 
>> little effect under low load, but improves performance by ~10% 
>> under high load. This has the side effect of making runtime
>> updates to the local_zone data non-instantaneous if there is a
>> conflicting entry in the cache, because the cache would be
>> consulted first. This side effect might be fixable by having
>> updates to the local_zone database do an implicit flush, which
>> adds some additional complexity, but it's probably worth doing
>> for up to a ~10% performance benefit under certain loads.
> 
> Very interesting, some optimizations can be made by making the
> local zone lookup better (and its locking).
> 
> However, moving the check after the cache check is not a good
> idea. The localzone and localdata statements are supposed to be
> able to override the DNS contents from the internet.  Checking it
> earlier means that this always happens.  Messing with cache flushes
> sounds very bad, a query may create a recursive query that would
> then override the configuration and so on, lots of complexity as
> well as worries about giving the 'wrong' answers (as compared to
> the configuration).


Am I wrong in assuming this would be a no-issue if localzone and
localdata would also enter the cache?

Best regards, jo