From: Furong Xu <0x1207@gmail.com> Date: Wed, 15 Jan 2025 03:27:03 +0000 (+0800) Subject: net: stmmac: Set page_pool_params.max_len to a precise size X-Git-Tag: v6.14-rc1~162^2~46^2~2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2324c78a75c54b4c49d22bb44fcccf5727ba5ef7;p=thirdparty%2Fkernel%2Flinux.git net: stmmac: Set page_pool_params.max_len to a precise size DMA engine will always write no more than dma_buf_sz bytes of a received frame into a page buffer, the remaining spaces are unused or used by CPU exclusively. Setting page_pool_params.max_len to almost the full size of page(s) helps nothing more, but wastes more CPU cycles on cache maintenance. For a standard MTU of 1500, then dma_buf_sz is assigned to 1536, and this patch brings ~16.9% driver performance improvement in a TCP RX throughput test with iPerf tool on a single isolated Cortex-A65 CPU core, from 2.43 Gbits/sec increased to 2.84 Gbits/sec. Signed-off-by: Furong Xu <0x1207@gmail.com> Reviewed-by: Alexander Lobakin Reviewed-by: Yanteng Si Signed-off-by: Paolo Abeni --- diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 1d98a5e8c98ca..811e2d372abf0 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -2059,7 +2059,7 @@ static int __alloc_dma_rx_desc_resources(struct stmmac_priv *priv, pp_params.dev = priv->device; pp_params.dma_dir = xdp_prog ? DMA_BIDIRECTIONAL : DMA_FROM_DEVICE; pp_params.offset = stmmac_rx_offset(priv); - pp_params.max_len = STMMAC_MAX_RX_BUF_SIZE(num_pages); + pp_params.max_len = dma_conf->dma_buf_sz; rx_q->page_pool = page_pool_create(&pp_params); if (IS_ERR(rx_q->page_pool)) { diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_xdp.h b/drivers/net/ethernet/stmicro/stmmac/stmmac_xdp.h index 896dc987d4ef3..77ce8cfbe976f 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_xdp.h +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_xdp.h @@ -4,7 +4,6 @@ #ifndef _STMMAC_XDP_H_ #define _STMMAC_XDP_H_ -#define STMMAC_MAX_RX_BUF_SIZE(num) (((num) * PAGE_SIZE) - XDP_PACKET_HEADROOM) #define STMMAC_RX_DMA_ATTR (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING) int stmmac_xdp_setup_pool(struct stmmac_priv *priv, struct xsk_buff_pool *pool,