On 8/26/20 5:54 AM, Tariq Toukan wrote:
> A single cacheline might not contain the packet header for
> small L1_CACHE_BYTES values.
> Use net_prefetch() as it issues an additional prefetch
> in this case.
>
> Signed-off-by: Tariq Toukan <tar...@mellanox.com>
> Reviewed-by: Saeed Mahameed <sae...@mellanox.com>
> ---
> drivers/net/ethernet/mellanox/mlx4/en_rx.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> index b50c567ef508..99d7737e8ad6 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> @@ -705,7 +705,7 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct
> mlx4_en_cq *cq, int bud
>
> frags = ring->rx_info + (index << priv->log_rx_info);
> va = page_address(frags[0].page) + frags[0].page_offset;
> - prefetchw(va);
> + net_prefetchw(va);
> /*
> * make sure we read the CQE after we read the ownership bit
> */
>
Why these cache lines would be written next ? Presumably we read the headers
(pulled into skb->head)
Really using prefetch() for the about to be read packet is too late anyway for
current cpus.
