Commit 123e8da1 authored by Maxim Mikityanskiy's avatar Maxim Mikityanskiy Committed by Daniel Borkmann
Browse files

xsk: Change the default frame size to 4096 and allow controlling it 



The typical XDP memory scheme is one packet per page. Change the AF_XDP
frame size in libbpf to 4096, which is the page size on x86, to allow
libbpf to be used with the drivers with the packet-per-page scheme.

Add a command line option -f to xdpsock to allow to specify a custom
frame size.

Signed-off-by: default avatarMaxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: default avatarTariq Toukan <tariqt@mellanox.com>
Acked-by: default avatarSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 2761ed4b

samples/bpf/xdpsock_user.c

+28 −16
Original line number Diff line number Diff line
@@ -68,6 +68,7 @@ static int opt_queue; 
static int opt_poll;

static int opt_interval = 1;

static u32 opt_xdp_bind_flags;

static int opt_xsk_frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE;

static __u32 prog_id;



struct xsk_umem_info {
@@ -276,6 +277,12 @@ static size_t gen_eth_frame(struct xsk_umem_info *umem, u64 addr) 
static struct xsk_umem_info *xsk_configure_umem(void *buffer, u64 size)

{

	struct xsk_umem_info *umem;

	struct xsk_umem_config cfg = {

		.fill_size = XSK_RING_PROD__DEFAULT_NUM_DESCS,

		.comp_size = XSK_RING_CONS__DEFAULT_NUM_DESCS,

		.frame_size = opt_xsk_frame_size,

		.frame_headroom = XSK_UMEM__DEFAULT_FRAME_HEADROOM,

	};

	int ret;



	umem = calloc(1, sizeof(*umem));
@@ -283,7 +290,7 @@ static struct xsk_umem_info *xsk_configure_umem(void *buffer, u64 size) 
		exit_with_error(errno);



	ret = xsk_umem__create(&umem->umem, buffer, size, &umem->fq, &umem->cq,

			       NULL);

			       &cfg);

	if (ret)

		exit_with_error(-ret);
@@ -323,11 +330,9 @@ static struct xsk_socket_info *xsk_configure_socket(struct xsk_umem_info *umem) 
				     &idx);

	if (ret != XSK_RING_PROD__DEFAULT_NUM_DESCS)

		exit_with_error(-ret);

	for (i = 0;

	     i < XSK_RING_PROD__DEFAULT_NUM_DESCS *

		     XSK_UMEM__DEFAULT_FRAME_SIZE;

	     i += XSK_UMEM__DEFAULT_FRAME_SIZE)

		*xsk_ring_prod__fill_addr(&xsk->umem->fq, idx++) = i;

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

		*xsk_ring_prod__fill_addr(&xsk->umem->fq, idx++) =

			i * opt_xsk_frame_size;

	xsk_ring_prod__submit(&xsk->umem->fq,

			      XSK_RING_PROD__DEFAULT_NUM_DESCS);
@@ -346,6 +351,7 @@ static struct option long_options[] = { 
	{"interval", required_argument, 0, 'n'},

	{"zero-copy", no_argument, 0, 'z'},

	{"copy", no_argument, 0, 'c'},

	{"frame-size", required_argument, 0, 'f'},

	{0, 0, 0, 0}

};
@@ -365,8 +371,9 @@ static void usage(const char *prog) 
		"  -n, --interval=n	Specify statistics update interval (default 1 sec).\n"

		"  -z, --zero-copy      Force zero-copy mode.\n"

		"  -c, --copy           Force copy mode.\n"

		"  -f, --frame-size=n   Set the frame size (must be a power of two, default is %d).\n"

		"\n";

	fprintf(stderr, str, prog);

	fprintf(stderr, str, prog, XSK_UMEM__DEFAULT_FRAME_SIZE);

	exit(EXIT_FAILURE);

}
@@ -377,7 +384,7 @@ static void parse_command_line(int argc, char **argv) 
	opterr = 0;



	for (;;) {

		c = getopt_long(argc, argv, "Frtli:q:psSNn:cz", long_options,

		c = getopt_long(argc, argv, "Frtli:q:psSNn:czf:", long_options,

				&option_index);

		if (c == -1)

			break;
@@ -420,6 +427,9 @@ static void parse_command_line(int argc, char **argv) 
		case 'F':

			opt_xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;

			break;

		case 'f':

			opt_xsk_frame_size = atoi(optarg);

			break;

		default:

			usage(basename(argv[0]));

		}
@@ -432,6 +442,11 @@ static void parse_command_line(int argc, char **argv) 
		usage(basename(argv[0]));

	}



	if (opt_xsk_frame_size & (opt_xsk_frame_size - 1)) {

		fprintf(stderr, "--frame-size=%d is not a power of two\n",

			opt_xsk_frame_size);

		usage(basename(argv[0]));

	}

}



static void kick_tx(struct xsk_socket_info *xsk)
@@ -583,8 +598,7 @@ static void tx_only(struct xsk_socket_info *xsk) 


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

				xsk_ring_prod__tx_desc(&xsk->tx, idx + i)->addr

					= (frame_nb + i) <<

					XSK_UMEM__DEFAULT_FRAME_SHIFT;

					= (frame_nb + i) * opt_xsk_frame_size;

				xsk_ring_prod__tx_desc(&xsk->tx, idx + i)->len =

					sizeof(pkt_data) - 1;

			}
@@ -661,21 +675,19 @@ int main(int argc, char **argv) 
	}



	ret = posix_memalign(&bufs, getpagesize(), /* PAGE_SIZE aligned */

			     NUM_FRAMES * XSK_UMEM__DEFAULT_FRAME_SIZE);

			     NUM_FRAMES * opt_xsk_frame_size);

	if (ret)

		exit_with_error(ret);



       /* Create sockets... */

	umem = xsk_configure_umem(bufs,

				  NUM_FRAMES * XSK_UMEM__DEFAULT_FRAME_SIZE);

	umem = xsk_configure_umem(bufs, NUM_FRAMES * opt_xsk_frame_size);

	xsks[num_socks++] = xsk_configure_socket(umem);



	if (opt_bench == BENCH_TXONLY) {

		int i;



		for (i = 0; i < NUM_FRAMES * XSK_UMEM__DEFAULT_FRAME_SIZE;

		     i += XSK_UMEM__DEFAULT_FRAME_SIZE)

			(void)gen_eth_frame(umem, i);

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

			(void)gen_eth_frame(umem, i * opt_xsk_frame_size);

	}



	signal(SIGINT, int_exit);

tools/lib/bpf/xsk.h

+1 −1
Original line number Diff line number Diff line
@@ -167,7 +167,7 @@ LIBBPF_API int xsk_socket__fd(const struct xsk_socket *xsk); 


#define XSK_RING_CONS__DEFAULT_NUM_DESCS      2048

#define XSK_RING_PROD__DEFAULT_NUM_DESCS      2048

#define XSK_UMEM__DEFAULT_FRAME_SHIFT    11 /* 2048 bytes */

#define XSK_UMEM__DEFAULT_FRAME_SHIFT    12 /* 4096 bytes */

#define XSK_UMEM__DEFAULT_FRAME_SIZE     (1 << XSK_UMEM__DEFAULT_FRAME_SHIFT)

#define XSK_UMEM__DEFAULT_FRAME_HEADROOM 0

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