[Bridge] Benchmarking bridging vs. routing on same hardware/network

[Dan Grigsby]

> Please try this patch,  it does:
>	* don't spin_lock on the update path unless entry
>	  is missing
>	* increase size of hash table
>	* use jenkins hash which might distribute better
>	* run gc timer at fixed interval.

I'll build a new kernel and let you know.  Thanks.

I've been working through the code and feel like I'm getting the feel of it.
The key was the NF_HOOK macro.

It's been ages since I wrote my own hash algorithm, so forgive a dumb
question: will a larger hash perform faster?  I only have a handful of mac
addresses to hash.  For me, ultimately this will be limited to 4 macs, one
for each interface and one for the single device attached to each Ethernet
segment.