FreeBSD boxes as a 'router'...

[Victor Balada Diaz]

On Tue, Nov 20, 2012 at 03:35:13PM +0000, John Fretby wrote:
> Howdy all,
> 
> We've currently got an ageing HP DL360 running as a 'router' - it has
> 100Mbit in/out onto our network, and has two 'bce' NIC's providing in/out.
> It's running quite an old version of FreeBSD (6 I think) - but works.
> 
> As the network gets busier we've noticed the amount of interrupt time on it
> is climbing (as you'd expect - i.e. esp. if many small packets are being
> forwarded). Many moons ago we did experiment with this box - and enabled
> device polling (inc. upping the HZ on the box and recompiling the kernel
> etc). This didn't work very well at the time (probably because it was in
> it's infancy) so we left it off in the end.
> 
> If we were to replace this box, with something new - say a SuperMicro based
> system with two:
> 
>    Intel 82574L's (em Driver Based)
> 
> And enable polling - is it likely to "just work" these days? The current
> upstream is 100Mbit, we're looking to upgrade this to 1Gbit in, but with
> say 200Mbit comitted on it (so shouldn't go above 200Mbit).
> 
> Is there anything that has to be done to enable polling - other than
> recompiling GENERIC to support it? - i.e. no HZ hacks or anything needed on
> 'modern' machines (it's a quad core Xeon).

Hello John,

You might find interesting to read this thread:

http://lists.freebsd.org/pipermail/freebsd-current/2012-November/037590.html

In short: device polling can decrease performance on modern hardware.

You might want to try upgrading to a new FreeBSD version and tuning it somehow
before buying a new server. More info on tuning the network stack:

http://wiki.freebsd.org/NetworkPerformanceTuning

Regards.
Victor.
-- 
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