Subject: Re: HTB accuracy for high speed (and bonding)

From: Vladimir Ivashchenko <[email-masked]>
Date: Sat, 23 May 2009 18:06:30 +0300

> > So, I got rid of bonding completely and instead configured PBR on Cisco
> > + Linux routing in such a way so that packet gets received and
> > transmitted using NICs connected to the same pair of cores with common
> > cache. 65-70% idle on all cores now, compared to 0-30% idle in worst
> > case scenarios before.
> 
> As a matter of fact I don't understand this bonding idea vs. smp: I
> guess Eric Dumazet wrote why it's wrong wrt. locking. I'm not an smp
> expert but I think the most efficient use is with separate NICs per
> cpu (so with separate HTB qdiscs if possible), or multiqueue NICs -

I tried the following scenario: 2 NICs used for receive + another 2 NICs 
used for transmit having HTB. Each NIC on a separate core. No bonding, 
just manual load balancing using IP routing.

The result was that RX cores would be 20% and 40% idle respectively, even 
though the amount of traffic they were receiving was roughly the same. 
The TX cores were idling at around 90%. 

I found this strange personally, but I'm completely ignorant in internals of
kernel operation.

-- 
Best Regards
Vladimir Ivashchenko
Chief Technology Officer
PrimeTel, Cyprus - www.prime-tel.com