Messages in this thread Patch in this message |  | | From | Furong Xu <> | | Subject | [PATCH net-next v2 3/3] net: stmmac: Optimize cache prefetch in RX path | | Date | Mon, 13 Jan 2025 22:20:31 +0800 |
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Current code prefetches cache lines for the received frame first, and then dma_sync_single_for_cpu() against this frame, this is wrong. Cache prefetch should be triggered after dma_sync_single_for_cpu().
This patch brings ~2.8% driver performance improvement in a TCP RX throughput test with iPerf tool on a single isolated Cortex-A65 CPU core, 2.84 Gbits/sec increased to 2.92 Gbits/sec.
Signed-off-by: Furong Xu <0x1207@gmail.com> --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index ca340fd8c937..b60f2f27140c 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -5500,10 +5500,6 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue) /* Buffer is good. Go on. */ - prefetch(page_address(buf->page) + buf->page_offset); - if (buf->sec_page) - prefetch(page_address(buf->sec_page)); - buf1_len = stmmac_rx_buf1_len(priv, p, status, len); len += buf1_len; buf2_len = stmmac_rx_buf2_len(priv, p, status, len); @@ -5525,6 +5521,7 @@ 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); xdp_init_buff(&ctx.xdp, buf_sz, &rx_q->xdp_rxq); xdp_prepare_buff(&ctx.xdp, page_address(buf->page), -- 2.34.1
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