Looks like igb on 12-ALPHA6 (driver 7.6.1-k) and on 11-STABLE (driver 2.5.3-k) behave very differently on receive [regression?]

[Eugene Grosbein]

23.09.2018 5:48, Lev Serebryakov wrote:

>>  Any hints?
>  I don't know why, but "server" host could not send more than 710Mbit/s with
> Ethernet flow control turned on. Turning flow control off helps.

Intel does not recommend MTU over 8.5KB for some NICs supported by igb(4) due to hardware problems:

https://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/i218-i219-ethernet-connection-spec-update.pdf