packet drop with intel gigabit / marwell gigabit

Lucas Holt luke at
Fri Mar 24 16:03:33 UTC 2006

On Mar 24, 2006, at 8:12 AM, OxY wrote:

> hi guys!
> well, i changed my motherboard and CPU  from the
> asus a7v8x+amd 2000+ xp to
> the abit be7 + p4 2.4 (533fsb)  and the packet loss fell down from  
> 8% to 2%, but
> still have loss...
> loss coming when i have load.. i guess it decreased because of the  
> bigger resources.
> still waiting for tipps, hints, everything :)

I don't think you'll ever get down to 0% in your situation.  I  
noticed in the initial post that you have  
net.inet.tcp.inflight.enable=1 set.  On my home network, turning that  
off helped a great deal with samba traffic to my freebsd file server/ 
router.  It didn't seem to affect traffic to my webserver much, but  
its very low traffic.  The problem with tuning on other people's  
settings is that each workload is different though.  There might not  
be a miracle hack to get this working how you want.  I'm sure the new  
box is a bit better as I attempted some of the steps outlined by Jin  
on my two machines.  (amd 2300+ w/ msi nforce2 512mb ram and P4  
2.4ghz 1gb ram 533mhz fsb)  The P4 system was faster on all my tests  
by quite a large margin.  I can't remember what version of FreeBSD  
you are using, but I do know they've done work on the em and fxp  
drivers during the 6.x series.  I noticed a big improvement from 5.4  
to 6.0 release and to 6.1 betas from 6.0 release.  You might have  
better luck when 6.1 release comes out.

I must admit, I didn't follow all of Jin's calculations.  I do think  
he's right about some motherboard chipsets having limitations that  
limit real world traffic on the bus though.  It follows what I  
learned in college during electrical engineering courses I was  
required to take.  Hardware and Software are a lot alike.  Just  
because something claims to support specific performance  
characteristics, does not mean that it does.  Windows is a great  
example.  I would guess that your problem is a combination of several  
factors including hardware, software, and network conditions.  Almost  
every time I've had a problem like this at work or home its been a  
wiring problem or a switch limiting the throughput.

Lucas Holt
Luke at
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