Re: [dpdk-dev] Performance issue with vmxnet3 pmd

["Patel, Rashmin N" <rashmin.n.patel@intel.com>]

Hi Hyunseok,

We should not compare Vmxnet3-PMD with ixgbe-PMD performance as Vmxnet3 device is a para-virtual device and it's not similar to directly assigned device to a VM either. 
There is VMEXIT/VMEXIT occurrence at burst-size boundary and that overhead can’t be eliminated unless the design of Vmxnet3 is updated in future. In addition to that the packets is being touched in ESXi hypervisor vSwitch layer between physical NIC and a virtual machine, which introduces extra overhead, which you won't have in case of using Niantic being used natively or passed through Vt-d to a virtual machine.

Feature wise, we can compare it to Virtio-PMD solution, but again there is a little different in device handling and backend driver support compared to Vmxnet3 device so performance comparison won’t to apple to apple.

Thanks,
Rashmin

-----Original Message-----
From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Hyunseok
Sent: Monday, July 07, 2014 3:22 PM
To: dev@dpdk.org
Subject: [dpdk-dev] Performance issue with vmxnet3 pmd

Hi,

I was testing l2-fwd with vmxnet3 pmd (included in dpdk).

The maximum forwarding rate I got from vmxnet3 pmd with l2fwd is only 2.5 to 2.8 Gbps.

This is in contrast with ixgbe pmd with which I could easily achieve 10 gbps forwarding rate.

With the original vmxnet3 driver (non pmd), I could also achieve close to
10 gpbs with multiple iperf.   But I can never achieve that rate with
vmxnet3 pmd...

So basically vmxnet3 pmd doesn't seem that fast.  Is this a known issue?

Thanks,
-Hyunseok