Passthrough for Cisco UCS VIC 1457 MLOM in vSphere 7.0.2

[Arne Bier]

Hello,

I have TREX 2.95 running on a Cisco UCS M5 under vShpere 7.0.2 - ESXi was installed using the Cisco specific .iso for the UCS family. ESXi has not been patched.

The UCS has a VIC 1457 MLOM adapter installed and I have been using it under TRex via the vSphere vSwitch. But I am hitting performance limitations and I wanted to use the Passthrough Mode instead. I deleted all the vSwitches and enabled Passthrough for the PCI adapter and the 4 uplinks. Rebooted ESXi. I can add the adapters to my VM as PCI adapters. But when I try to power on the VM, I always get the error "The operation is not allowed in the current state of the host". I have to delete the PCI adapters from the VM to allow the VM to boot again. 

I have done the following

- updated UCS and all components to latest 4.2.2 firmware 

- enabled the Kernel "disable ACS check" option as per google search recommendations

Nothing works. Anyone had success using this adapter in Passthrough Mode?

I allocated 16 vCPUs to TREX and with a -c 4 switch it reports in the console that it sees 8 CORES. Even with 8 cores I cannot exceed 2Gbps on a single interface.

What sort of tweaking is required to make trex work faster under VMWare?

- jumbo frames enable?

- buffer tuning in CIMC ?

- larger payloads in the UDP datagrams that are being sent?

- even more vCPU allocated?

- Passthrough Mode?

- trex YAML config file tweaking??

regards