On 2/10/2020 8:31 AM, Jason Gunthorpe wrote:
On Mon, Feb 10, 2020 at 08:18:05AM -0500, Dennis Dalessandro wrote:
This patch series is an accelerated ipoib using the rdma netdev mechanism
already present in ipoib. A new device capability bit,
IB_DEVICE_RDMA_NETDEV_OPA, triggers ipoib to create a datagram QP using the
IB_QP_CREATE_NETDEV_USE.
The highlights include:
- Sharing send and receive resources with VNIC
- Allows for switching between connected mode and datagram mode
There is still value in connected mode?
It's really a compatibility thing. If someone wants to change modes that
will work. There won't be any benefit to connected mode though. The goal
is just to not break.
>> - Increases the maximum datagram MTU for opa devices to 10k
The same spreading capability exploited by VNIC is used here to vary
the receive context that receives the packet.
The patches are fully bisectable and stepwise implement the capability.
This is alot of code to send without a performance
justification.. What is it? Is it worth while?
It avoids the scalability problem of connected mode, the number of QPs.
Incoming packets are spread into multiple receive contexts increasing
parallelism. The MTU is increased to allows 10K. It also reduces/removes
the verbs TX overhead by allowing packets to be sent through the SDMA
engines directly.
Gary Leshner (6):
IB/hfi1: Add functions to transmit datagram ipoib packets
IB/hfi1: Add the transmit side of a datagram ipoib RDMA netdev
IB/hfi1: Remove module parameter for KDETH qpns
IB/{rdmavt,hfi1}: Implement creation of accelerated UD QPs
IB/{hfi1,ipoib,rdma}: Broadcast ping sent packets which exceeded mtu size
IB/ipoib: Add capability to switch between datagram and connected mode
Grzegorz Andrejczuk (7):
IB/hfi1: RSM rules for AIP
IB/hfi1: Rename num_vnic_contexts as num_netdev_contexts
IB/hfi1: Add functions to receive accelerated ipoib packets
IB/hfi1: Add interrupt handler functions for accelerated ipoib
IB/hfi1: Add rx functions for dummy netdev
This dummy netdev thing seemed very strange
One of the existing uses of dummy netdev seems to be to tie multiple
hardware interfaces together. We are using a similar concept for two
software interfaces. Those being VNIC and AIP. The dummy netdev here
will own the receiving resources which are shared.
-Denny
