From e1ee1e62bec4a8968355517ea11b2a06b7364408 Mon Sep 17 00:00:00 2001 From: Dag Moxnes Date: Wed, 30 Oct 2019 13:44:00 +0100 Subject: RDMA/cma: Use ACK timeout for RoCE packetLifeTime MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 CA’s ACK delay). Assuming a negligible local ACK delay, we can use PacketLifeTime = local ACK timeout/2 as a reasonable approximation for RoCE networks. Link: https://lore.kernel.org/r/1572439440-17416-1-git-send-email-dag.moxnes@oracle.com Signed-off-by: Dag Moxnes Reviewed-by: Jason Gunthorpe Signed-off-by: Jason Gunthorpe --- drivers/infiniband/core/cma.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'drivers/infiniband') diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c index abf249d277ad..25f2b70fd8ef 100644 --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -2504,7 +2504,9 @@ EXPORT_SYMBOL(rdma_set_service_type); * This function should be called before rdma_connect() on active side, * and on passive side before rdma_accept(). It is applicable to primary * path only. The timeout will affect the local side of the QP, it is not - * negotiated with remote side and zero disables the timer. + * negotiated with remote side and zero disables the timer. In case it is + * set before rdma_resolve_route, the value will also be used to determine + * PacketLifeTime for RoCE. * * Return: 0 for success */ @@ -2913,7 +2915,16 @@ static int cma_resolve_iboe_route(struct rdma_id_private *id_priv) route->path_rec->rate = iboe_get_rate(ndev); dev_put(ndev); route->path_rec->packet_life_time_selector = IB_SA_EQ; - route->path_rec->packet_life_time = CMA_IBOE_PACKET_LIFETIME; + /* In case ACK timeout is set, use this value to calculate + * PacketLifeTime. As per IBTA 12.7.34, + * local ACK timeout = (2 * PacketLifeTime + Local CA’s ACK delay). + * Assuming a negligible local ACK delay, we can use + * PacketLifeTime = local ACK timeout/2 + * as a reasonable approximation for RoCE networks. + */ + route->path_rec->packet_life_time = id_priv->timeout_set ? + id_priv->timeout - 1 : CMA_IBOE_PACKET_LIFETIME; + if (!route->path_rec->mtu) { ret = -EINVAL; goto err2; -- cgit v1.2.3