Commit f78bd130 authored by Björn Töpel's avatar Björn Töpel Committed by Tony Nguyen
Browse files

i40e, xsk: remove HW descriptor prefetch in AF_XDP path 



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: default avatarBjörn Töpel <bjorn.topel@intel.com>
Tested-by: default avatarAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: default avatarTony Nguyen <anthony.l.nguyen@intel.com>
parent 1fa5cef2

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

+13 −0
Original line number Diff line number Diff line
@@ -2295,6 +2295,19 @@ 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

drivers/net/ethernet/intel/i40e/i40e_txrx_common.h

+0 −13
Original line number Diff line number Diff line
@@ -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);

drivers/net/ethernet/intel/i40e/i40e_xsk.c

+12 −0
Original line number Diff line number Diff line
@@ -257,6 +257,18 @@ 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