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

Furong Xu
2025-01-15T03:27:48Z

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>
---
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