1 Reply Latest reply on Nov 20, 2018 5:17 AM by vikiz

    100Gbit slow on Epyc HW.


      we recognize slow speed on an AMD H11SSL-i single socked Boards with the latest Bios 1.0C



      Two servers connected over a Mellanox SN2100 switch.MSN2100


      Bios settings

      C-State disabled

      IO-SVR disabled

      SMV enabled

      Perforamce mode enabled


      On this setup, we run an Ubuntu Kernel 4.15.0-37.40,

      but we recognize this problem also with the 4.19.1 mainline kernel

      and an old ubuntu 4.4 Kernel.


      We use to try two different kinds of nic

      First the Mellanox MCX556A-ECAT

      Second the Mellanox MCX456A-ECAT


      The problem is with an iperf3 parallel benchmark test

      we only reach 60GBit on the MCX556A-ECAT and 50GBit on the MCX456A-ECAT.

      With an Intel Broadwell (SuperMicro X10SRi-F Board), the iperf3 test shows results near 90 GBit what is ok with Spectre and Meltdown mediation.


      Has anyone an Idea what could be the reason?