em performs worse than igb (latency wise) in 12?

Matthew Macy mmacy at freebsd.org
Sat Apr 6 22:49:17 UTC 2019

On Sat, Apr 6, 2019 at 1:23 PM Michael Butler
<imb at protected-networks.net> wrote:
> On 2019-04-06 08:58, Kris von Mach wrote:
> > On 4/6/2019 2:56 AM, Pete French wrote:
> >> Something odd going on there there - I am using 12-STABLE and I have
> >> igb just fine, and it attaches to the same hardware that 11 did:
> >
> > I ran apache bench, and I got a result of 100 requests/sec on 12-STABLE
> > vs 16,000 requests/sec on 11-STABLE. So something is definitely wrong.
> > Nothing changed other than going from 11 to 12.
> I'd be interested to see if substituting the port net/intel-em-kmod has
> any effect on the issue,

I would as well. igb, em, and lem are all the same driver in 12. This
makes maintenance a lot easier. However, the older NICs have a lot of
errata workarounds that aren't explicitly commented as such. My first
guess is this card suffers from one such errata workaround that has
been dropped in the update.


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