[plug] PPPoE tuning

[Bernd Felsche]

Tomasz Grzegurzko <tomasz_g at arach.net.au> writes:
>Quoting Bernd Felsche <bernie at innovative.iinet.net.au>:
>> Tomasz Grzegurzko <tomasz_g at arach.net.au> writes:
>> >Quoting Bernd Felsche <bernie at innovative.iinet.net.au>:

>> >> I've recently connected to ADSL2+. My newer firewall is a Pentium
>> >> MMX @ 200MHz with "minimal" SuSE 10.0 and shiny new kernel installed.
>> 
>> >> The firewall is running rp-pppoe and it's maxed out on CPU at about
>> >> 14,000 kbps.  Most of the CPU usage is in kernel mode so it's
>> >> obviously doing important stuff in the ppp module.
>> 
>> >> Is there any obvious tuning that I could be doing?
>> 
>> >Are you sure its actually running in kernel mode and not user mode?
>> 
>> The SuSE doc says that the pppoe uses kernel mode. Under load, only
>> about 20% is in user space and 80% in kernel.

>> >rp-pppoe takes a bit of work to get running in kernel mode; I
>> >didn't see any difference once I got it going in kernel space
>> >(but I'm on 256/64).

>> I read that there are some tuning options in the documentation but
>> don't yet understand which ones will have the best effect.

>So when the link is down; you see a drop in the load?

With the link down, the system is at least 99.9% idle.

With the link up and no traffic, idle is nearly the same; about
99.8% or more. When listening to lo-fi web radio (@ around 56kbps),
idle plummets to a minimum of about 98.6% (5 second averages).

When I shove the spammers bots an unpalatable diet of continuous
SMTP responses, idle drops as low as 94%.

>I just wonder if its something other than pppoe - a net card perhaps?

Erm... I doubt that very much.

>(in which case you may try enabling NAPI for example).

I believe that those changes were rolled into the 2.6 kernel while
ago. SuSE 10.0 uses 2.6.13 as a base.

As the modem is connected by Ethernet, I've read that I shouldn't
define that interface but how would the pppd talk to the modem
without a device?  It doesn't work for me.
-- 
/"\ Bernd Felsche - Innovative Reckoning, Perth, Western Australia
\ /  ASCII ribbon campaign | Socialist \So"cial*ist\, n.
 X   against HTML mail     | One who knows what's best for
/ \  and postings          | everyone else.