[Pdns-users] Re: Pdns and packet cache efficiency

karthik karthikszone at gmail.com
Fri Mar 14 07:14:22 UTC 2008


> I have been stress testing powerdns with pgsql backend - specifically
> the efficiency of packet cache. The max qps i get out of it is 7.5K and 
> a packetcache hit rate of 75%. It seems that pdns essentially uses a 
> single cpu when its cache is filled.
> A colleague mentioned that the cache is accessed via a select(2) loop,
> which runs a single thread and performance improvement would be possible
> by replacing the select() loop with epoll(4).
> Is this possible ? Can pdns use all available cpu's to lookup from cache
> ? It seems to me that using a single CPU is the bottleneck..

Anyone had a chance to look at this ? Iam very interested in knowing why the
cache   access uses single CPU - It looks it can gain more with using multiple 

It would be great if someone can shed more light on this.


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