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

[Brad Knowles]

At 6:50 AM +0900 2005-02-21, JINMEI Tatuya / 
=?ISO-2022-JP?B?GyRCP0BMQEMjOkgbKEI=?= wrote:

>  (I don't know who is OP, but) I know, and I thought I had tried to
>  provide information based on this fact.

	My apologies.  I got the impression that you were offering advice 
for operations of BIND9, as opposed to testing.

>  Again, yes, and I already agreed that BIND9 should eventually provide
>  better performance with threading.  I don't think it contradicts
>  suggesting turn threading off for the moment as an operational nit.

	As a temporary operational nit while tracking down other issues, 
I have no problem with that advice.

>  I would first like to note once again that I was talking about one
>  particular case where we have two CPUs.

	I missed that part.  It wasn't clear to me whether we were 
talking about single or multiple CPU systems, and that's why I tried 
to cover both sets of issues.

>                       But could you be more specific on what threaded
>  BIND9 can provide on a single CPU?  In my understanding, BIND9
>  carefully decomposes its tasks into small chunks and avoids using
>  blocking APIs so that every single task (in BIND9) will not make
>  others wait for a long period.

	My understanding was that BIND9 had all the same blocking issues 
as BIND8, unless run with threading enabled.  Perhaps this is 
different for BIND 9.2.x versus 9.3.x?  Or maybe I just missed 
something really fundamental?

>  Regarding the former, I admit my experiences in this area are limited,
>  but from my experiences with {FreeBSD, Linux, Solaris, True64} on
>  {Xeon, opteron, sparc, alpha}, I've almost never seen the case where
>  threaded BIND9 provide better performance than a single process of
>  BIND8...

	On a single CPU, yes -- that is to be expected.  On two or more 
CPUs, a single instance of BIND9 should outrun a single instance of 
BIND8, everything else being equal.

	If we can't do that, then I think we might as well go home.

-- 
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.