Re: [PATCH net-next v3 4/4] net: stmmac: Convert prefetch() to net_prefetch() for received frames

Larysa Zaremba
2025-01-15T16:36:10Z

On Wed, Jan 15, 2025 at 11:27:05AM +0800, Furong Xu wrote:
> The size of DMA descriptors is 32 bytes at most.
> net_prefetch() for received frames, and keep prefetch() for descriptors.
>
> This patch brings ~4.8% driver performance improvement in a TCP RX
> throughput test with iPerf tool on a single isolated Cortex-A65 CPU
> core, 2.92 Gbits/sec increased to 3.06 Gbits/sec.
>
> Suggested-by: Joe Damato <jdamato@fastly.com>
> Signed-off-by: Furong Xu <0x1207@gmail.com>

Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>

> ---
> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index ad928e8e21a9..49b41148d594 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -5529,7 +5529,8 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
>
> dma_sync_single_for_cpu(priv->device, buf->addr,
> buf1_len, dma_dir);
> - prefetch(page_address(buf->page) + buf->page_offset);
> + net_prefetch(page_address(buf->page) +
> + buf->page_offset);
>
> xdp_init_buff(&ctx.xdp, buf_sz, &rx_q->xdp_rxq);
> xdp_prepare_buff(&ctx.xdp, page_address(buf->page),
> --
> 2.34.1
>
>