| Message ID | 20240913110259.1220314-1-0x1207@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,v1] net: stmmac: set PP_FLAG_DMA_SYNC_DEV only if XDP is enabled | expand |
On 9/13/24 13:02, Furong Xu wrote: > When XDP is not enabled, the page which holds the received buffer > will be recycled once the buffer is copied into SKB by > skb_copy_to_linear_data(), then the MAC core will never reuse this > page any longer. Set PP_FLAG_DMA_SYNC_DEV wastes CPU cycles. > > This patch brings up to 9% noticeable performance improvement on > certain platforms. > > Fixes: 5fabb01207a2 ("net: stmmac: Add initial XDP support") > Signed-off-by: Furong Xu <0x1207@gmail.com> I'm quite unconvinced that every performance improvement would be eligible to be considered a fix. Reading the code it looks like this change actually addresses a regression introduced by the blamed commit, is that correct? If so please re-phrase the commit message accordingly. Thanks, Paolo
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index f3a1b179aaea..95d3d1081727 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -2022,7 +2022,7 @@ static int __alloc_dma_rx_desc_resources(struct stmmac_priv *priv, rx_q->queue_index = queue; rx_q->priv_data = priv; - pp_params.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV; + pp_params.flags = PP_FLAG_DMA_MAP | (xdp_prog ? PP_FLAG_DMA_SYNC_DEV : 0); pp_params.pool_size = dma_conf->dma_rx_size; num_pages = DIV_ROUND_UP(dma_conf->dma_buf_sz, PAGE_SIZE); pp_params.order = ilog2(num_pages);
When XDP is not enabled, the page which holds the received buffer will be recycled once the buffer is copied into SKB by skb_copy_to_linear_data(), then the MAC core will never reuse this page any longer. Set PP_FLAG_DMA_SYNC_DEV wastes CPU cycles. This patch brings up to 9% noticeable performance improvement on certain platforms. Fixes: 5fabb01207a2 ("net: stmmac: Add initial XDP support") Signed-off-by: Furong Xu <0x1207@gmail.com> --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)