[Samba] Re: samba on quad core vs dual core

[Volker Lendecke]

On Tue, Dec 09, 2008 at 03:17:53PM -0500, Andy Liebman wrote:
> 
> >Samba will use all the cores you can give it - so long as
> >you have at least more clients than cores.
> >
> >Jeremy.
> >  
> While I have found that to be true in my environment, I have also found 
> that MOST smbd's end up on Core 0 MOST of the time.  This is true even 
> if I am hammering a 10 Gigabit network adapter (i.e., sending out 700 
> MB/sec via Samba distributed to 30 users), with total CPU utilization 
> only about 70 percent of one core.

Have you measured how much you can pump out over that
adapter using raw tcp using, say, iperf or so? My guess
would be that 700MBytes/second are not way off what it can
do.

> Maybe this is optimal behavior.  I tried to start a thread on this  list 
> a while back about understanding what WOULD be optimal, and nobody had 
> much to say.

If you really only use 70% of one core, then my feeling
would be that this is indeed what you should expect for
cache locality. But to say for sure a *lot* deeper
investigations are necessary.

Volker
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