dummynet, em driver, device polling issues :-((

[Kevin Day]

On Oct 4, 2005, at 7:00 AM, Ferdinand Goldmann wrote:
>
> Ok, to followup on this issue:
>
> Today I installed the driver which I had downloaded from the Intel  
> website (em-3.2.15.tar.gz). This driver does not solve the issue  
> with Ierrs rising rapidly when polling is enabled (I tried HZ=1000  
> and burst_max 300 and 600).
>
> Neither throughput nor interrupt load were any better than with the  
> old driver; in fact I'd say they were worse. :-( So we ended up  
> rebooting with the old kernel.
>
> This is pretty bad, because we did assume that Intel cards are  
> among the ones well supported by FreeBSD.
>
> Can anyone give recommendations on copper Gbit cards that work  
> _well_ with recent FreeBSD 5-STABLE?


This is pretty odd. We've got dozens of servers using various  
versions of 5.x, and many different em cards, and have no problem,  
even when shoving near line rate speeds out of them.

Add in cards like:

em0: <Intel(R) PRO/1000 Network Connection, Version - 1.7.35> port  
0xccc0-0xccff mem 0xfcd20000-0xfcd3ffff irq 24 at device 6.0 on pci2


and built in to newer Dell servers:

em0: <Intel(R) PRO/1000 Network Connection, Version - 1.7.35> port  
0xecc0-0xecff mem 0xdfae0000-0xdfafffff irq 64 at device 7.0 on pci6


After you experience your problems, can you do "sysctl -w  
hw.em0.stats=1" and "sysctl -w hw.em0.debug_info=1" and post what  
gets dumped to your syslog/dmesg output?

We're using polling on nearly all the servers, and don't see ierrs at  
all. Have you tried contacting Intel directly about this?  
freebsdnic at mailbox.intel.com has been pretty helpful with em specific  
problems in the past.