Re: [PATCH rdma-next] RDMA/cma: Use ACK timeout for RoCE packetLifeTime

From: Jason Gunthorpe
Date: Tue Oct 29 2019 - 15:51:07 EST

On Fri, Oct 25, 2019 at 01:42:01PM +0200, Dag Moxnes wrote:
> The cma is currently using a hard-coded value, CMA_IBOE_PACKET_LIFETIME,
> for the PacketLifeTime, as it can not be determined from the network.
> This value might not be optimal for all networks.
> The cma module supports the function rdma_set_ack_timeout to set the
> ACK timeout for a QP associated with a connection. As per IBTA 12.7.34
> local ACK timeout = (2 * PacketLifeTime + Local CAâs ACK delay).
> Assuming a negligible local ACK delay, we can use
> PacketLifeTime = local ACK timeout/2
> as a reasonable approximation for RoCE networks.
> Signed-off-by: Dag Moxnes <dag.moxnes@xxxxxxxxxx>
> Change-Id: I200eda9d54829184e556c3c55d6a8869558d76b2

Please don't send Change-Id to the public lists. Run checkpatch before

Otherwise this seems reasonable to me..