Commit 700f11eb authored by Horatiu Vultur's avatar Horatiu Vultur Committed by Jakub Kicinski
Browse files

lan966x: Don't use xdp_frame when action is XDP_TX 



When the action of an xdp program was XDP_TX, lan966x was creating
a xdp_frame and use this one to send the frame back. But it is also
possible to send back the frame without needing a xdp_frame, because
it is possible to send it back using the page.
And then once the frame is transmitted is possible to use directly
page_pool_recycle_direct as lan966x is using page pools.
This would save some CPU usage on this path, which results in higher
number of transmitted frames. Bellow are the statistics:
Frame size:    Improvement:
64                ~8%
256              ~11%
512               ~8%
1000              ~0%
1500              ~0%

Signed-off-by: default avatarHoratiu Vultur <horatiu.vultur@microchip.com>
Reviewed-by: default avatarAlexander Lobakin <aleksander.lobakin@intel.com>
Link: https://lore.kernel.org/r/20230422142344.3630602-1-horatiu.vultur@microchip.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent ee3392ed

drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c

+23 −12
Original line number Diff line number Diff line
@@ -390,6 +390,7 @@ static void lan966x_fdma_stop_netdev(struct lan966x *lan966x) 
static void lan966x_fdma_tx_clear_buf(struct lan966x *lan966x, int weight)

{

	struct lan966x_tx *tx = &lan966x->tx;

	struct lan966x_rx *rx = &lan966x->rx;

	struct lan966x_tx_dcb_buf *dcb_buf;

	struct xdp_frame_bulk bq;

	struct lan966x_db *db;
@@ -432,7 +433,8 @@ static void lan966x_fdma_tx_clear_buf(struct lan966x *lan966x, int weight) 
			if (dcb_buf->xdp_ndo)

				xdp_return_frame_bulk(dcb_buf->data.xdpf, &bq);

			else

				xdp_return_frame_rx_napi(dcb_buf->data.xdpf);

				page_pool_recycle_direct(rx->page_pool,

							 dcb_buf->data.page);

		}



		clear = true;
@@ -699,15 +701,14 @@ static void lan966x_fdma_tx_start(struct lan966x_tx *tx, int next_to_use) 
	tx->last_in_use = next_to_use;

}



int lan966x_fdma_xmit_xdpf(struct lan966x_port *port,

			   struct xdp_frame *xdpf,

			   struct page *page,

			   bool dma_map)

int lan966x_fdma_xmit_xdpf(struct lan966x_port *port, void *ptr, u32 len)

{

	struct lan966x *lan966x = port->lan966x;

	struct lan966x_tx_dcb_buf *next_dcb_buf;

	struct lan966x_tx *tx = &lan966x->tx;

	struct xdp_frame *xdpf;

	dma_addr_t dma_addr;

	struct page *page;

	int next_to_use;

	__be32 *ifh;

	int ret = 0;
@@ -722,8 +723,13 @@ int lan966x_fdma_xmit_xdpf(struct lan966x_port *port, 
		goto out;

	}



	/* Get the next buffer */

	next_dcb_buf = &tx->dcbs_buf[next_to_use];



	/* Generate new IFH */

	if (dma_map) {

	if (!len) {

		xdpf = ptr;



		if (xdpf->headroom < IFH_LEN_BYTES) {

			ret = NETDEV_TX_OK;

			goto out;
@@ -743,11 +749,16 @@ int lan966x_fdma_xmit_xdpf(struct lan966x_port *port, 
			goto out;

		}



		next_dcb_buf->data.xdpf = xdpf;

		next_dcb_buf->len = xdpf->len + IFH_LEN_BYTES;



		/* Setup next dcb */

		lan966x_fdma_tx_setup_dcb(tx, next_to_use,

					  xdpf->len + IFH_LEN_BYTES,

					  dma_addr);

	} else {

		page = ptr;



		ifh = page_address(page) + XDP_PACKET_HEADROOM;

		memset(ifh, 0x0, sizeof(__be32) * IFH_LEN);

		lan966x_ifh_set_bypass(ifh, 1);
@@ -756,21 +767,21 @@ int lan966x_fdma_xmit_xdpf(struct lan966x_port *port, 
		dma_addr = page_pool_get_dma_addr(page);

		dma_sync_single_for_device(lan966x->dev,

					   dma_addr + XDP_PACKET_HEADROOM,

					   xdpf->len + IFH_LEN_BYTES,

					   len + IFH_LEN_BYTES,

					   DMA_TO_DEVICE);



		next_dcb_buf->data.page = page;

		next_dcb_buf->len = len + IFH_LEN_BYTES;



		/* Setup next dcb */

		lan966x_fdma_tx_setup_dcb(tx, next_to_use,

					  xdpf->len + IFH_LEN_BYTES,

					  len + IFH_LEN_BYTES,

					  dma_addr + XDP_PACKET_HEADROOM);

	}



	/* Fill up the buffer */

	next_dcb_buf = &tx->dcbs_buf[next_to_use];

	next_dcb_buf->use_skb = false;

	next_dcb_buf->data.xdpf = xdpf;

	next_dcb_buf->xdp_ndo = dma_map;

	next_dcb_buf->len = xdpf->len + IFH_LEN_BYTES;

	next_dcb_buf->xdp_ndo = !len;

	next_dcb_buf->dma_addr = dma_addr;

	next_dcb_buf->used = true;

	next_dcb_buf->ptp = false;

drivers/net/ethernet/microchip/lan966x/lan966x_main.h

+2 −4
Original line number Diff line number Diff line
@@ -243,6 +243,7 @@ struct lan966x_tx_dcb_buf { 
	union {

		struct sk_buff *skb;

		struct xdp_frame *xdpf;

		struct page *page;

	} data;

	u32 len;

	u32 used : 1;
@@ -541,10 +542,7 @@ int lan966x_ptp_setup_traps(struct lan966x_port *port, struct ifreq *ifr); 
int lan966x_ptp_del_traps(struct lan966x_port *port);



int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev);

int lan966x_fdma_xmit_xdpf(struct lan966x_port *port,

			   struct xdp_frame *frame,

			   struct page *page,

			   bool dma_map);

int lan966x_fdma_xmit_xdpf(struct lan966x_port *port, void *ptr, u32 len);

int lan966x_fdma_change_mtu(struct lan966x *lan966x);

void lan966x_fdma_netdev_init(struct lan966x *lan966x, struct net_device *dev);

void lan966x_fdma_netdev_deinit(struct lan966x *lan966x, struct net_device *dev);

drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c

+3 −7
Original line number Diff line number Diff line
@@ -62,7 +62,7 @@ int lan966x_xdp_xmit(struct net_device *dev, 
		struct xdp_frame *xdpf = frames[i];

		int err;



		err = lan966x_fdma_xmit_xdpf(port, xdpf, NULL, true);

		err = lan966x_fdma_xmit_xdpf(port, xdpf, 0);

		if (err)

			break;
@@ -76,7 +76,6 @@ int lan966x_xdp_run(struct lan966x_port *port, struct page *page, u32 data_len) 
{

	struct bpf_prog *xdp_prog = port->xdp_prog;

	struct lan966x *lan966x = port->lan966x;

	struct xdp_frame *xdpf;

	struct xdp_buff xdp;

	u32 act;
@@ -90,11 +89,8 @@ int lan966x_xdp_run(struct lan966x_port *port, struct page *page, u32 data_len) 
	case XDP_PASS:

		return FDMA_PASS;

	case XDP_TX:

		xdpf = xdp_convert_buff_to_frame(&xdp);

		if (!xdpf)

			return FDMA_DROP;



		return lan966x_fdma_xmit_xdpf(port, xdpf, page, false) ?

		return lan966x_fdma_xmit_xdpf(port, page,

					      data_len - IFH_LEN_BYTES) ?

		       FDMA_DROP : FDMA_TX;

	case XDP_REDIRECT:

		if (xdp_do_redirect(port->dev, &xdp, xdp_prog))