Re: [gentoo-user] Rate limiting TCP connections...

Mick wrote:
> I think that the problem is associated with the way that the Linux box treats
> bind requests.  Other than QoS which will try to allocate some bandwidth to
> bind packets, or nice which will elevate bind's processes - you may want to
> check your kernel's IO scheduler and set it to something that will give each
> process an equal bite of the cherry.  Trial & error may get you there.
>
I don't think QOS is the right answer - since I've never seen this 
problem before - and I've never used QOS on Linux before.  I think that 
the scheduler might explain things far better. I half-remember something 
about the inclusion of the new "CFS" scheduler when I compiled the 
kernel - maybe the default changed when I moved to the 2.6.23-gentoo-r3 
kernel from - erm - some older 2.6 version many months ago.

Maybe I should upgrade to the latest kernel (I'm reluctant to do this in 
a hurry - since I've lost my notes on which kernel options I'd activated 
- and it's a 'live' box I'm using on a day-to-day basis that I'd rather 
not break. Doah!)
> A workaround to avoid WinXP name requests timing out is to manually set at
> your WinXP clients the Netgear's IP address as their secondary DNS server.
>
That's a fantastic hack... I like the idea... though, obviously, if it 
were trivial, I'd prefer Bind on gentoo not to hang. ;)
>> My router is a "Netgear Wireless ADSL Firewall Router" - it seems pretty
>> common... and I've not found other people moaning that it has
>> problems...  For me, it only has problems when accessed from my Linux box.
>>
> I used to run a Netgear DG834 and did not notice anything like this.  After a
> few seconds the Gentoo and WinXP clients would share the bandwidth -
> irrespective of which one started downloading first.  WinXP might have been
> slightly more hesitant to start with, but after say 30 seconds it would even
> out.  However, this was with wired full duplex connections.  Wireless is half
> duplex, transmit and receive happens sequentially not in parallel - when
> downloading on the Gentoo goes at full pelt it may take longer for inbound
> packets to get to bind and this could make the rather short TTL that
> MSWindows has to time out.
>
That's encouraging.  Always good to know that there are no 'known' 
bugs... I was caught out by this a few years ago with a DLink router - 
where I assumed it was my FreeBSD box at fault - but, actually, the 
router had broken firmware.
> PS. Have you tried this with two Linux clients (use Knoppix on one of your
> MSWindows boxen)?
>
No, I could, I guess - but I'm 95% convinced now that this is an I/O 
scheduling issue on my Gentoo box - and is not an issue with my router.

Many thanks.