[Intel-wired-lan] [next PATCH S32 06/14] i40e/i40evf: Faster RX via avoiding fcoe

[Harshitha Ramamurthy]

From: Jesse Brandeburg <jesse.brandeburg at intel.com>

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.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg at intel.com>
Change-ID: I080552c26e7060bc7b78504dc2763f6f0b3d8c76
---
Testing Hints: Make sure rx still works, and that
perf top doesn't show i40e_handle_fcoe_status.
 
 drivers/net/ethernet/intel/i40e/i40e_txrx.c   |  8 ++++++--
 drivers/net/ethernet/intel/i40e/i40e_txrx.h   | 10 ++++++++++
 drivers/net/ethernet/intel/i40evf/i40e_txrx.c |  4 +++-
 drivers/net/ethernet/intel/i40evf/i40e_txrx.h | 10 ++++++++++
 4 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index f4e4d3d..29ffed2 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/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;
 		}
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
index 681e9bc..4b08d47 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h
+++ b/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_ */
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
index ec1f447..0c912a4 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
+++ b/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;
 		}
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.h b/drivers/net/ethernet/intel/i40evf/i40e_txrx.h
index 6cf1169..92deb97 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.h
+++ b/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_ */
-- 
2.4.3