9.2.5 db causes high cpu? was: Re: BIND 9.2.5rc1 is now available.

Brad Knowles brad at stop.mail-abuse.org
Sun Feb 20 16:33:22 UTC 2005


At 12:43 PM +0900 2005-02-20, JINMEI Tatuya / 
=?ISO-2022-JP?B?GyRCP0BMQEMjOkgbKEI=?= wrote:

>  Perhaps I was not really clear...I didn't mean running two BIND9
>  processes disabling threads is a feasible long-term solution.  I just
>  clarified the current status of BIND9 threading and tried to make a
>  realistic solution for the current real problem (of someone) based on
>  the fact.

	Okay, fair enough.  However, the OP was testing out BIND9.  He 
wasn't in a situation where he was absolutely required to run BIND9, 
and therefore would need whatever tips or hacks that people can offer 
to try to get something semi-reasonably working.

	In the case of the OP, he's pointing out issues that he's running 
into with BIND9 when trying to use it pretty much the same way as he 
is using BIND8 on all of his other machines, and this is a clear 
indicator of an issue that needs to be addressed within the code.

>  I must admit I jumped in some sense though.  What we should first try
>  is that running a *single* process of BIND9 disabling threads.  If it
>  can provide necessary response performance (with moderate CPU usage),
>  we are done.

	If you had said "moderate CPU usage and moderate memory usage", I 
might have bought that argument, even considering that the threading 
model is one of the big advantages that BIND9 is supposed to have 
over BIND8.  But throwing out threading and using excessive memory is 
not an adequate solution for this testing, even if we can get the CPU 
utilization down.

>  In any case, I don't think running a single process enabling threads
>  helps in this situation, since it even won't run faster (much) than
>  a single non-threading process.

	Threading is not about speed, at least not on a single CPU 
system.  Threading in BIND9 is about the other things it can do for 
you, while providing roughly comparable straight-out performance.

	Now, when you talk about SMP machines, threading in BIND9 should 
definitely provide better performance than a single instance of BIND8 
on the same machine, and it should be able to provide roughly 
comparable performance to a number of BIND8 instances equal to the 
number of CPUs in the system.

-- 
Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.


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