The 11/16/2022 16:45, Alexander Lobakin wrote: > [Some people who received this message don't often get email from alexandr.lobakin@xxxxxxxxx. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] > > From: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx> > Date: Tue, 15 Nov 2022 22:44:52 +0100 > > > Update the page_pool params to allocate XDP_PACKET_HEADROOM space as > > headroom for all received frames. > > This is needed for when the XDP_TX and XDP_REDIRECT are implemented. > > > > Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx> > > [...] > > > @@ -466,6 +470,7 @@ static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx, > > > > skb_mark_for_recycle(skb); > > > > + skb_reserve(skb, XDP_PACKET_HEADROOM); > > Oh, forgot to ask previously. Just curious, which platforms do > usually have this NIC? Do those platforms have > CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS set? I am running on ARM and I can see that CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS is set. > If no, then adding %NET_SKB_PAD to the headroom can significantly > improve performance, as currently you have 28 bytes of IFH + 14 > bytes of Eth header, so IP header is not aligned to 4 bytes > boundary. Kernel and other drivers often expect IP header to be > aligned. Adding %NET_SKB_PAD to the headroom addresses that. > ...but be careful, I've just realized that you have IFH in front > of Eth header, that means that it will also become unaligned after > that change, so make sure you don't access it with words bigger > than 2 bytes. Just test all the variants and pick the best :D Thanks for a detail explanation! > > > skb_put(skb, FDMA_DCB_STATUS_BLOCKL(db->status)); > > > > lan966x_ifh_get_timestamp(skb->data, ×tamp); > > @@ -786,7 +791,8 @@ static int lan966x_fdma_get_max_frame(struct lan966x *lan966x) > > return lan966x_fdma_get_max_mtu(lan966x) + > > IFH_LEN_BYTES + > > SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) + > > - VLAN_HLEN * 2; > > + VLAN_HLEN * 2 + > > + XDP_PACKET_HEADROOM; > > } > > [...] > > > -- > > 2.38.0 > > Thanks, > Olek -- /Horatiu
