Re: [PATCH rdma-next 00/10] Enable relaxed ordering for ULPs

Jason Gunthorpe
2021-04-14T14:49:15Z

On Wed, Apr 14, 2021 at 02:41:52PM +0000, David Laight wrote:

> So whatever driver initialises the target needs to configure whatever
> target-specific register enables the RO transfers themselves.

RDMA in general, and mlx5 in particular, is a layered design:

mlx5_core <- owns the PCI function, should turn on RO at the PCI
function level
mlx5_en <- Commands the chip to use RO for queues used in ethernet
ib_core
ib_uverbs
mlx5_ib <- Commands the chip to use RO for some queues used in
userspace
ib_srp* <- A ULP driver built on RDMA - this patch commands the chip
to use RO on SRP queues
nvme-rdma <- Ditto
ib_iser <- Ditto
rds <- Ditto

So this series is about expanding the set of queues running on mlx5
that have RO turned when the PCI function is already running with RO
enabled.

We want as many queues as possible RO enabled because it brings big
performance wins

Jason