[Intel-wired-lan] [PATCH net-next 1/4] i40e, xsk: remove HW descriptor prefetch in AF_XDP path
Björn Töpel
bjorn.topel at gmail.com
Thu Jul 2 15:37:27 UTC 2020
From: Björn Töpel <bjorn.topel at intel.com>
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 at intel.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(-)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 3e5c566ceb01..e1a76fc05b8d 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -2299,6 +2299,19 @@ void i40e_finalize_xdp_rx(struct i40e_ring *rx_ring, unsigned int xdp_res)
}
}
+/**
+ * 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
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h b/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
index 667c4dc4b39f..1397dd3c1c57 100644
--- 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_programming_status(u64 qword1)
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);
diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
index 8ce57b507a21..1f2dd591dbf1 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
@@ -253,6 +253,18 @@ static struct sk_buff *i40e_construct_skb_zc(struct i40e_ring *rx_ring,
return skb;
}
+/**
+ * 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
--
2.25.1
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