NVIDIA MLX5 Introducing Data Direct Placement “DDP” In Linux 6.13 For Boosting Bandwidth

The NVIDIA MLX5 driver for NVIDIA Mellanox ConnectX-5 network adapters is preparing to introduce a new Data Direct Placement “DDP” feature with the upcoming Linux 6.13 kernel merge window.

The Data Direct Placement feature for Mellanox RDMA hardware allows for the user to consume data out of order from RDMA write and send operations while the completion ordering remains in order. With Data Direct Placement the intent is on achieving higher bandwidth by permitting responders to receive packets out of order. Paired with the multi-plane support this can net big bandwidth wins for the data path.

I have yet to see the NVIDIA engineers involved publish any performance benchmarks of the Data Direct Placement feature besides noting on the mailing lists that their results have been positive and should yield a nice improvement to bandwidth.

The DDP patches for the MLX5 driver and related patches have been queued into RDMA.git’s “for-next” branch ahead of the Linux 6.13 merge window opening next week. The Linux 6.13 kernel in turn should be out as stable around late January or early February.