Commit 284cbc61 authored by Björn Töpel's avatar Björn Töpel Committed by Daniel Borkmann
Browse files

samples/bpf: Use recvfrom() in xdpsock/l2fwd 



Start using recvfrom() the l2fwd scenario, instead of poll() which is
more expensive and need additional knobs for busy-polling.

Signed-off-by: default avatarBjörn Töpel <bjorn.topel@intel.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarMagnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20201130185205.196029-9-bjorn.topel@gmail.com
parent f2d27282

samples/bpf/xdpsock_user.c

+12 −14
Original line number Diff line number Diff line
@@ -1098,8 +1098,7 @@ static void kick_tx(struct xsk_socket_info *xsk) 
	exit_with_error(errno);

}



static inline void complete_tx_l2fwd(struct xsk_socket_info *xsk,

				     struct pollfd *fds)

static inline void complete_tx_l2fwd(struct xsk_socket_info *xsk)

{

	struct xsk_umem_info *umem = xsk->umem;

	u32 idx_cq = 0, idx_fq = 0;
@@ -1134,7 +1133,8 @@ static inline void complete_tx_l2fwd(struct xsk_socket_info *xsk, 
				exit_with_error(-ret);

			if (xsk_ring_prod__needs_wakeup(&umem->fq)) {

				xsk->app_stats.fill_fail_polls++;

				ret = poll(fds, num_socks, opt_timeout);

				recvfrom(xsk_socket__fd(xsk->xsk), NULL, 0, MSG_DONTWAIT, NULL,

					 NULL);

			}

			ret = xsk_ring_prod__reserve(&umem->fq, rcvd, &idx_fq);

		}
@@ -1331,19 +1331,19 @@ static void tx_only_all(void) 
		complete_tx_only_all();

}



static void l2fwd(struct xsk_socket_info *xsk, struct pollfd *fds)

static void l2fwd(struct xsk_socket_info *xsk)

{

	unsigned int rcvd, i;

	u32 idx_rx = 0, idx_tx = 0;

	int ret;



	complete_tx_l2fwd(xsk, fds);

	complete_tx_l2fwd(xsk);



	rcvd = xsk_ring_cons__peek(&xsk->rx, opt_batch_size, &idx_rx);

	if (!rcvd) {

		if (xsk_ring_prod__needs_wakeup(&xsk->umem->fq)) {

			xsk->app_stats.rx_empty_polls++;

			ret = poll(fds, num_socks, opt_timeout);

			recvfrom(xsk_socket__fd(xsk->xsk), NULL, 0, MSG_DONTWAIT, NULL, NULL);

		}

		return;

	}
@@ -1353,7 +1353,7 @@ static void l2fwd(struct xsk_socket_info *xsk, struct pollfd *fds) 
	while (ret != rcvd) {

		if (ret < 0)

			exit_with_error(-ret);

		complete_tx_l2fwd(xsk, fds);

		complete_tx_l2fwd(xsk);

		if (xsk_ring_prod__needs_wakeup(&xsk->tx)) {

			xsk->app_stats.tx_wakeup_sendtos++;

			kick_tx(xsk);
@@ -1388,22 +1388,20 @@ static void l2fwd_all(void) 
	struct pollfd fds[MAX_SOCKS] = {};

	int i, ret;



	for (;;) {

		if (opt_poll) {

			for (i = 0; i < num_socks; i++) {

				fds[i].fd = xsk_socket__fd(xsks[i]->xsk);

				fds[i].events = POLLOUT | POLLIN;

	}



	for (;;) {

		if (opt_poll) {

			for (i = 0; i < num_socks; i++)

				xsks[i]->app_stats.opt_polls++;

			}

			ret = poll(fds, num_socks, opt_timeout);

			if (ret <= 0)

				continue;

		}



		for (i = 0; i < num_socks; i++)

			l2fwd(xsks[i], fds);

			l2fwd(xsks[i]);



		if (benchmark_done)

			break;