Exposing full 32bit RSS hash from card for ixgbe(4)

[Barney Cordoba]

What's the point of all of this gobbledygook anyway? Seriously, 99% of the world needs a driver that passes packets in the most efficient way, and every time I look at igb and ixgbe it has another 2 heads. It's up to 8 heads, and none of the things wrong with it have been fixed. This is now even uglier than Kip Macy's cxgb abortion.
I'm not trying to be snarky here. I wrote a simple driver 3 years ago that runs and runs and uses little cpu; maybe 8% for a full gig load on an E3. What is the benefit of implementing all of these stupid offload and RSS hashes? Spreading across cpus is incredibly inefficient; running 8 'queues' on a quad core cpu with hyperthreading is incredibly stupid. 1 cpu can easily handle a full gig, so why are you dirtying the code with 8000 "features" when it runs just fine without any of them? you're subjecting 1000s of users to constant instability (and fear in upgrading at all) for what amounts to a college science project. I know you haven't benchmarked it, so why are you doing it? hell, you added that buf_ring stuff without even making any determination that it was beneficial to use it, just because it was there.
You're trying to steal a handful of cycles with these hokey features, and then you're losing buckets of cycles (maybe wheelbarrows) by unnecessarily spreading the processes across too many cpus. It just makes no sense at all.
If you want to play, that's fine. But there should be simple I/O drivers for em, igb and ixgbe available as alternatives for the 99% of users who just want to run a router, a bridge/filter or a web server. Drivers that don't break features A and C when you make a change to Q and Z because you can't possibly test all 8000 features every time you do something.
Im horrified that some poor schlub with a 1 gig webserver is losing half of his cpu power because of the ridiculous defaults in the igb driver. 


     On Wednesday, July 15, 2015 2:01 PM, hiren panchasara <hiren at freebsd.org> wrote:
   

 On 07/14/15 at 02:18P, hiren panchasara wrote:
> On 07/14/15 at 12:38P, Eric Joyner wrote:
> > Sorry for the delay; it looked fine to me, but I never got back to you.
> > 
> > - Eric
> > 
> > On Mon, Jul 13, 2015 at 3:16 PM Adrian Chadd <adrian.chadd at gmail.com> wrote:
> > 
> > > Hi,
> > >
> > > It's fine by me. Please do it!
> 
> Thanks Adrian and Eric. Committed as r285528.
FYI:

I am planning to do a partial mfc of this to stable10. Here is the
patch:
https://people.freebsd.org/~hiren/patches/ix_expose_rss_hash_stable10.patch

(I did the same for igb(4), r282831)

Cheers,
Hiren