svn commit: r238765 - head/sys/dev/e1000

[John Baldwin]

On Wednesday, July 25, 2012 7:28:15 am Luigi Rizzo wrote:
> Author: luigi
> Date: Wed Jul 25 11:28:15 2012
> New Revision: 238765
> URL: http://svn.freebsd.org/changeset/base/238765
> 
> Log:
>   Use legacy interrupts as a default. This gives up to 10% speedup
>   when used in qemu (and this driver is for non-PCIe cards,
>   so probably its largest use is in virtualized environments).
>   
>   Approved by:	Jack Vogel
>   MFC after:	3 days

Why not make this a tunable or some such?  You could even have it only use the 
legacy handler under qemu easily enough.  There's no reason this has to be a 
compile-time option.  This is almost certainly slower on real hardware where 
this is important to work around dubious Intel Host-PCI bridges that result in 
aliased USB interrupts for every em(4) interrupt.

-- 
John Baldwin