DNS Performance Numbers

Dave kreios at gmail.com
Wed Nov 22 15:45:29 UTC 2006


On Nov 18, 2006, at 7:52 AM, O. Hartmann wrote:

> Marcelo Gardini do Amaral wrote:
>>> FYI: In response to feedback from ISC, there are UDP transmit  
>>> optimizations
>>> in FreeBSD 7.x.  These have a relatively minor performance impact  
>>> for
>>> single-threaded applications, but in the special case of BIND  
>>> accessing a
>>> single UDP socket from many different threads, it significantly  
>>> improves
>>> performance.  I'll look at MFC'ing these to 6.x after 6.2-RELEASE
>>> (especially if reminded in a month or so :-).
>>>
>>> With regard to the possible bge issue -- I would encourage you to  
>>> test
>>> using a 7.x kernel, ideally with all the debugging disabled, and  
>>> see if
>>> there's been any improvement (or regression).  There has been a  
>>> lot of
>>> change in these areas, and it would be helpful to know what, if  
>>> any, impact
>>> this has had.
>>>
>>
>>
>> I made some tests using 7.x with all the debugging disabled:
>>
>>                                 queries / s
>>
>> Int     bind (d_t)      bind (e_t)      nsd (1_s)       nsd (2_s)
>> ---     ----------      ----------      ---------       ---------
>>
>> bge     15439           14733           12910           10946
>> em      37655           34092           42411           41974
>>
>>
>> d_t: disable threads
>> e_t: enable threads (libpthread)
>> 1_s: 1 server forked
>> 2_s: 2 server forked
>>
>> Bind: 9.2.3
>> NSD: 3.0.2
>> em: Dell 1950, Intel NIC, SMP kernel
>> bge: HP Blade BL35p, Broadcom NIC, SMP kernel
>> Client: Dell 1750, Intel NIC, FreeBSD 4.11 UP, running queryperf
>>
>>
>>
>> The results are very good for em NIC, better than my numbers [1] with
>> FreeBSD 6.1 some months ago. So I guess that we had an  
>> improvement :-)
>>
>> But I got the same poor performance with the bge interface. The
>> problem remains.
>>
>> [1] http://lists.freebsd.org/pipermail/freebsd-net/2006-September/ 
>> 011767.html
>>
>> Cheers,
>> Marcelo
>>
>>
>
>
> These results looks very puzzling to me.
> As far as I know, multithreading and/or multiprocessors should perform
> better anyway than a single threaded application within other
> applications on an UP box. Strange results ...And more strange than  
> this
> is the result taken from the FBSD 4.11 box! Is there an explanation  
> why
> FreeBSD performs so bad beyond 4.X and on SMP boxes? Please show me
> threads ...
>
> Thanks and regards,
> Oliver

The FreeBSD pthread library and BIND don't work well together.  If  
you use the libthr library, performance goes up.

--
Dave



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