i40e/i40evf: Faster RX via avoiding FCoE

As it turns out, calling into other files from hot path hurts
performance a lot.  In this case the majority of the time we
call "check FCoE" and the packet is *not* FCoE, but this call
was taking 5% of our total cycles spent on receive.

Change-ID: I080552c26e7060bc7b78504dc2763f6f0b3d8c76
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_fcoe.c

 /*******************************************************************************
  *
  * Intel Ethernet Controller XL710 Family Linux Driver
- * Copyright(c) 2013 - 2015 Intel Corporation.
+ * Copyright(c) 2013 - 2016 Intel Corporation.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -37,16 +37,6 @@
 #include "i40e.h"
 #include "i40e_fcoe.h"
 
-/**
- * i40e_rx_is_fcoe - returns true if the rx packet type is FCoE
- * @ptype: the packet type field from rx descriptor write-back
- **/
-static inline bool i40e_rx_is_fcoe(u16 ptype)
-{
-	return (ptype >= I40E_RX_PTYPE_L2_FCOE_PAY3) &&
-	       (ptype <= I40E_RX_PTYPE_L2_FCOE_VFT_FCOTHER);
-}
-
 /**
  * i40e_fcoe_sof_is_class2 - returns true if this is a FC Class 2 SOF
  * @sof: the FCoE start of frame delimiter

drivers/net/ethernet/intel/i40e/i40e_txrx.c

@@ -1703,7 +1703,9 @@ static int i40e_clean_rx_irq_ps(struct i40e_ring *rx_ring, const int budget)
 			 ? le16_to_cpu(rx_desc->wb.qword0.lo_dword.l2tag1)
 			 : 0;
 #ifdef I40E_FCOE
-		if (!i40e_fcoe_handle_offload(rx_ring, rx_desc, skb)) {
+		if (unlikely(
+		    i40e_rx_is_fcoe(rx_ptype) &&
+		    !i40e_fcoe_handle_offload(rx_ring, rx_desc, skb))) {
 			dev_kfree_skb_any(skb);
 			continue;
 		}
@@ -1834,7 +1836,9 @@ static int i40e_clean_rx_irq_1buf(struct i40e_ring *rx_ring, int budget)
 			 ? le16_to_cpu(rx_desc->wb.qword0.lo_dword.l2tag1)
 			 : 0;
 #ifdef I40E_FCOE
-		if (!i40e_fcoe_handle_offload(rx_ring, rx_desc, skb)) {
+		if (unlikely(
+		    i40e_rx_is_fcoe(rx_ptype) &&
+		    !i40e_fcoe_handle_offload(rx_ring, rx_desc, skb))) {
 			dev_kfree_skb_any(skb);
 			continue;
 		}

drivers/net/ethernet/intel/i40e/i40e_txrx.h

@@ -448,4 +448,14 @@ static inline bool i40e_chk_linearize(struct sk_buff *skb, int count)
 
 	return __i40e_chk_linearize(skb);
 }
+
+/**
+ * i40e_rx_is_fcoe - returns true if the Rx packet type is FCoE
+ * @ptype: the packet type field from Rx descriptor write-back
+ **/
+static inline bool i40e_rx_is_fcoe(u16 ptype)
+{
+	return (ptype >= I40E_RX_PTYPE_L2_FCOE_PAY3) &&
+	       (ptype <= I40E_RX_PTYPE_L2_FCOE_VFT_FCOTHER);
+}
 #endif /* _I40E_TXRX_H_ */

drivers/net/ethernet/intel/i40evf/i40e_txrx.c

@@ -1160,7 +1160,9 @@ static int i40e_clean_rx_irq_ps(struct i40e_ring *rx_ring, const int budget)
 			 ? le16_to_cpu(rx_desc->wb.qword0.lo_dword.l2tag1)
 			 : 0;
 #ifdef I40E_FCOE
-		if (!i40e_fcoe_handle_offload(rx_ring, rx_desc, skb)) {
+		if (unlikely(
+		    i40e_rx_is_fcoe(rx_ptype) &&
+		    !i40e_fcoe_handle_offload(rx_ring, rx_desc, skb))) {
 			dev_kfree_skb_any(skb);
 			continue;
 		}

drivers/net/ethernet/intel/i40evf/i40e_txrx.h

@@ -430,4 +430,14 @@ static inline bool i40e_chk_linearize(struct sk_buff *skb, int count)
 
 	return __i40evf_chk_linearize(skb);
 }
+
+/**
+ * i40e_rx_is_fcoe - returns true if the Rx packet type is FCoE
+ * @ptype: the packet type field from Rx descriptor write-back
+ **/
+static inline bool i40e_rx_is_fcoe(u16 ptype)
+{
+	return (ptype >= I40E_RX_PTYPE_L2_FCOE_PAY3) &&
+	       (ptype <= I40E_RX_PTYPE_L2_FCOE_VFT_FCOTHER);
+}
 #endif /* _I40E_TXRX_H_ */