RDMA/cxgb3: Turn off RX coalescing for iWARP connections
authorSteve Wise <swise@opengridcomputing.com>
Sun, 19 Sep 2010 00:38:21 +0000 (19:38 -0500)
committerRoland Dreier <rolandd@cisco.com>
Mon, 27 Sep 2010 16:28:55 +0000 (09:28 -0700)
commitbec658ff31453a5726b1c188674d587a5d40c482
tree68a8a1977e100e4f4fb2f7631eff79fefe463a13
parent32163f4b2cef28a5aab8b226ffecfc6379a53786
RDMA/cxgb3: Turn off RX coalescing for iWARP connections

The HW by default has RX coalescing on.  For iWARP connections, this
causes a 100ms delay in connection establishement due to the ingress
MPA Start message being stalled in HW.  So explicitly turn RX
coalescing off when setting up iWARP connections.

This was causing very bad performance for NP64 gather operations using
Open MPI, due to the way it sets up connections on larger jobs.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Cc: <stable@kernel.org>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
drivers/infiniband/hw/cxgb3/iwch_cm.c