Problems with em interfaces on FreeBSD 6.1

[Jack Vogel]

On 8/11/06, Landon Fuller <landonf at opendarwin.org> wrote:
>
> We saw this issue here on SMP systems running 6.1; I've been meaning
> to set up a reproduction case in the lab and dig into the issue further.
> Disabling the mpsafe network stack (debug.mpsafenet=0) is our
> temporary work-around; rwatson mentioned that this has the effect of
> forcing the interrupt handler for if_em to not run in parallel with
> the transmit code, which is likely what caused the problem to disappear.

Hmmm, I have code running right now that is required for new hardware, but
I think will benefit all, that only has the hardware writeback and interrupt on
the EOP descriptor. As it is now we have every descriptor written back.
I havent had it put thru extensive tests yet, but I expect it to significantly
reduce interrupts.

I hope to be submitting this stuff together with TSO support to CURRENT
soon, stay tuned.

Jack
Intel LAD