From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= <bjorn.topel@intel.com>
Date: Tue, 25 Aug 2020 13:35:54 +0200
Subject: i40e, xsk: remove HW descriptor prefetch in AF_XDP path
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Patch-mainline: v5.10-rc1
Git-commit: f78bd13027d9d43a6f5f3469377cd6bfd4218a14
References: jsc#SLE-13701
The software prefetching of HW descriptors has a negative impact on
the performance. Therefore, it is now removed.
Performance for the rx_drop benchmark increased with 2%.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
drivers/net/ethernet/intel/i40e/i40e_txrx.c | 13 +++++++++++++
drivers/net/ethernet/intel/i40e/i40e_txrx_common.h | 13 -------------
drivers/net/ethernet/intel/i40e/i40e_xsk.c | 12 ++++++++++++
3 files changed, 25 insertions(+), 13 deletions(-)
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -2296,6 +2296,19 @@ void i40e_finalize_xdp_rx(struct i40e_ri
}
/**
+ * i40e_inc_ntc: Advance the next_to_clean index
+ * @rx_ring: Rx ring
+ **/
+static void i40e_inc_ntc(struct i40e_ring *rx_ring)
+{
+ u32 ntc = rx_ring->next_to_clean + 1;
+
+ ntc = (ntc < rx_ring->count) ? ntc : 0;
+ rx_ring->next_to_clean = ntc;
+ prefetch(I40E_RX_DESC(rx_ring, ntc));
+}
+
+/**
* i40e_clean_rx_irq - Clean completed descriptors from Rx ring - bounce buf
* @rx_ring: rx descriptor ring to transact packets on
* @budget: Total limit on number of packets to process
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
@@ -99,19 +99,6 @@ static inline bool i40e_rx_is_programmin
return qword1 & I40E_RXD_QW1_LENGTH_SPH_MASK;
}
-/**
- * i40e_inc_ntc: Advance the next_to_clean index
- * @rx_ring: Rx ring
- **/
-static inline void i40e_inc_ntc(struct i40e_ring *rx_ring)
-{
- u32 ntc = rx_ring->next_to_clean + 1;
-
- ntc = (ntc < rx_ring->count) ? ntc : 0;
- rx_ring->next_to_clean = ntc;
- prefetch(I40E_RX_DESC(rx_ring, ntc));
-}
-
void i40e_xsk_clean_rx_ring(struct i40e_ring *rx_ring);
void i40e_xsk_clean_tx_ring(struct i40e_ring *tx_ring);
bool i40e_xsk_any_rx_ring_enabled(struct i40e_vsi *vsi);
--- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
@@ -258,6 +258,18 @@ static struct sk_buff *i40e_construct_sk
}
/**
+ * i40e_inc_ntc: Advance the next_to_clean index
+ * @rx_ring: Rx ring
+ **/
+static void i40e_inc_ntc(struct i40e_ring *rx_ring)
+{
+ u32 ntc = rx_ring->next_to_clean + 1;
+
+ ntc = (ntc < rx_ring->count) ? ntc : 0;
+ rx_ring->next_to_clean = ntc;
+}
+
+/**
* i40e_clean_rx_irq_zc - Consumes Rx packets from the hardware ring
* @rx_ring: Rx ring
* @budget: NAPI budget