Re: [LSF/MM/BPF TOPIC] NVMe over MPTCP: Multi-Fold Acceleration for NVMe over TCP in Multi-NIC Environments

[Geliang Tang <geliang@kernel.org>]

Hi Nilay,

Thanks for your reply.

On Wed, 2026-02-25 at 20:37 +0530, Nilay Shroff wrote:
> 
> 
> On 1/29/26 9:43 AM, Geliang Tang wrote:
> > 3. Performance Benefits
> > 
> > This new feature has been evaluated in different environments:
> > 
> > I conducted 'NVMe over MPTCP' tests between two PCs, each equipped
> > with
> > two Gigabit NICs and directly connected via Ethernet cables. Using
> > 'NVMe over TCP', the fio benchmark showed a speed of approximately
> > 100
> > MiB/s. In contrast, 'NVMe over MPTCP' achieved about 200 MiB/s with
> > fio, doubling the throughput.
> > 
> > In a virtual machine test environment simulating four NICs on both
> > sides, 'NVMe over MPTCP' delivered bandwidth up to four times that
> > of
> > standard TCP.
> 
> This is interesting. Did you try using an NVMe multipath iopolicy
> other
> than the default numa policy? Assuming both the host and target are
> multihomed,
> configuring round-robin or queue-depth may provide performance
> comparable
> to what you are seeing with MPTCP.
> 
> I think MPTCP shall distribute traffic using transport-level metrics
> such as
> RTT, cwnd, and packet loss, whereas the NVMe multipath layer makes
> decisions
> based on ANA state, queue depth, and NUMA locality. In a setup with
> multiple
> active paths, switching the iopolicy from numa to round-robin or
> queue-depth
> could improve load distribution across controllers and thus improve
> performance.
> 
> IMO, it would be useful to test with those policies and compare the
> results
> against the MPTCP setup.

Ming Lei also made a similar comment. In my experiments, I didn't set
the multipath iopolicy, so I was using the default numa policy. In the
follow-up, I'll adjust it to round-robin or queue-depth and rerun the
experiments. I'll share the results in this email thread.

Thanks,
-Geliang

> 
> Thanks,
> --Nilay