Multiqueue support for bpf

[Takuya ASADA]

Sorry for late replying,

> One comment, one question.
>
> First, I think we should try to integrate this work and then tune it up more.  The API
> is, I think, fine, and performance tuning takes a bit of work.

Is there good way(I mean tools or something) to find the bottleneck?

> Second, what are the parameters set on buffers for the drivers?  I.e. how many slots
> do they have in their queues etc.?  If they defaults are too small, and often they are,
> then that's going to hurt your performance.

It does equals to number of descriptors per queue, right?
If I'm correct, it's 2048 descriptors per queue by default, and I used
default parameter when I perform benchmarks.

It's on line 290 of
http://p4db.freebsd.org/fileViewer.cgi?FSPC=//depot/projects/soc2011/mq_bpf/src/sys/dev/ixgbe/ixgbe.c&REV=2

and line 105 of
http://p4db.freebsd.org/fileViewer.cgi?FSPC=//depot/projects/soc2011/mq_bpf/src/sys/dev/ixgbe/ixgbe.h&REV=2