[ewg] [PATCH ofed-1.5.2 2/2] cxgb3: Turn off RX coalescing for iwarp connections.

[Steve Wise]

This drops the connect latency from 200ms to 16.  Needed for large
NP clusters.

Signed-off-by: Steve Wise <swise at opengridcomputing.com>
---

 .../fixes/iw_cxgb3_1300_rx_coalesce_off.patch      |   24 ++++++++++++++++++++
 1 files changed, 24 insertions(+), 0 deletions(-)
 create mode 100644 kernel_patches/fixes/iw_cxgb3_1300_rx_coalesce_off.patch

diff --git a/kernel_patches/fixes/iw_cxgb3_1300_rx_coalesce_off.patch b/kernel_patches/fixes/iw_cxgb3_1300_rx_coalesce_off.patch
new file mode 100644
index 0000000..958b3b5
--- /dev/null
+++ b/kernel_patches/fixes/iw_cxgb3_1300_rx_coalesce_off.patch
@@ -0,0 +1,24 @@
+diff --git a/drivers/infiniband/hw/cxgb3/iwch_cm.c b/drivers/infiniband/hw/cxgb3/iwch_cm.c
+index 52d7bb0..687a647 100644
+--- a/drivers/infiniband/hw/cxgb3/iwch_cm.c
++++ b/drivers/infiniband/hw/cxgb3/iwch_cm.c
+@@ -486,7 +486,8 @@ static int send_connect(struct iwch_ep *ep)
+ 	    V_MSS_IDX(mtu_idx) |
+ 	    V_L2T_IDX(ep->l2t->idx) | V_TX_CHANNEL(ep->l2t->smt_idx);
+ 	opt0l = V_TOS((ep->tos >> 2) & M_TOS) | V_RCV_BUFSIZ(rcv_win>>10);
+-	opt2 = V_FLAVORS_VALID(1) | V_CONG_CONTROL_FLAVOR(cong_flavor);
++	opt2 = F_RX_COALESCE_VALID | V_RX_COALESCE(0) | V_FLAVORS_VALID(1) |
++	       V_CONG_CONTROL_FLAVOR(cong_flavor);
+ 	skb->priority = CPL_PRIORITY_SETUP;
+ 	set_arp_failure_handler(skb, act_open_req_arp_failure);
+ 
+@@ -1302,7 +1303,8 @@ static void accept_cr(struct iwch_ep *ep, __be32 peer_ip, struct sk_buff *skb)
+ 	    V_MSS_IDX(mtu_idx) |
+ 	    V_L2T_IDX(ep->l2t->idx) | V_TX_CHANNEL(ep->l2t->smt_idx);
+ 	opt0l = V_TOS((ep->tos >> 2) & M_TOS) | V_RCV_BUFSIZ(rcv_win>>10);
+-	opt2 = V_FLAVORS_VALID(1) | V_CONG_CONTROL_FLAVOR(cong_flavor);
++	opt2 = F_RX_COALESCE_VALID | V_RX_COALESCE(0) | V_FLAVORS_VALID(1) |
++	       V_CONG_CONTROL_FLAVOR(cong_flavor);
+ 
+ 	rpl = cplhdr(skb);
+ 	rpl->wr.wr_hi = htonl(V_WR_OP(FW_WROPCODE_FORWARD));