em driver packet loss in 6.2 amd64 (RELEASE and STABLE)

[Garrett Cooper]

Rob Watt wrote:
> Hi,
>
> In 6.1-RELEASE there were a number of em driver stability and 
> performance issues. We would regularly see packet loss at low to 
> moderate load. A number of patches were applied that completely fixed 
> the problem for us.
>
> We installed 6.2-RELEASE, but even though 6.2 is supposed to have a 
> stable em driver, we are noticing the same packet loss problem again. 
> We updated to STABLE, and we didn't see any packet drops in our first 
> day of testing, but today we are seeing packet drops again.
>
> Has anyone else experienced this? Are there known problems with the 
> STABLE em driver?
>
> Our hardware:
>
>   tyan s5372 motherboard (bios v1.05)
>   2 intel x5355 processors
>   adaptec aic7902 scsi daughter card
>   there are 4 em interfaces (2 on-board, 2 from an add-on card), but we
>     are currently only using em0
>
> We have experienced the packet drop problem with a custom kernel and 
> with the RELEASE SMP kernel.
>
> -
> Rob Watt
    I saw a little bit of this when using vmware and a newly installed 
6.2 guest machine. The problem was related to the amount of time it took 
for ssh to a real 7-CURRENT box to adjust the window size (interestingly 
enough). It took 15 ~ 20 additional seconds for it to adjust and later 
connect.
    This all occurred post authentication phase -- and I'm pretty sure 
it was the last step before connecting.
-Garrett