[RFC PATCH bpf-next 13/14] i40e: prefetch xdp->data before running XDP prog

[Toshiaki Makita]

XDP progs are likely to read/write xdp->data.
This improves the performance of xdp_flow.
This is included in this series just to demonstrate to what extent
xdp_flow performance can increase.

Signed-off-by: Toshiaki Makita <toshiaki.maki...@gmail.com>
---
 drivers/net/ethernet/intel/i40e/i40e_txrx.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c 
b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index f162252..ea775ae 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -2207,6 +2207,7 @@ static struct sk_buff *i40e_run_xdp(struct i40e_ring 
*rx_ring,
        if (!xdp_prog)
                goto xdp_out;
 
+       prefetchw(xdp->data);
        prefetchw(xdp->data_hard_start); /* xdp_frame write */
 
        act = bpf_prog_run_xdp(xdp_prog, xdp);
-- 
1.8.3.1