samples/bpf: Add busy-poll support to xdpsock

Add a new option to xdpsock, 'B', for busy-polling. This option will
also set the batching size, 'b' option, to the busy-poll budget.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20201130185205.196029-10-bjorn.topel@gmail.com

diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c
index a1a3d6f..4622a17 100644 (file)
--- a/samples/bpf/xdpsock_user.c
+++ b/samples/bpf/xdpsock_user.c
@@ -95,6 +95,7 @@ static int opt_timeout = 1000;
 static bool opt_need_wakeup = true;
 static u32 opt_num_xsks = 1;
 static u32 prog_id;
+static bool opt_busy_poll;
 
 struct xsk_ring_stats {
        unsigned long rx_npkts;
@@ -911,6 +912,7 @@ static struct option long_options[] = {
        {"quiet", no_argument, 0, 'Q'},
        {"app-stats", no_argument, 0, 'a'},
        {"irq-string", no_argument, 0, 'I'},
+       {"busy-poll", no_argument, 0, 'B'},
        {0, 0, 0, 0}
 };
 
@@ -949,6 +951,7 @@ static void usage(const char *prog)
                "  -Q, --quiet          Do not display any stats.\n"
                "  -a, --app-stats      Display application (syscall) statistics.\n"
                "  -I, --irq-string     Display driver interrupt statistics for interface associated with irq-string.\n"
+               "  -B, --busy-poll      Busy poll.\n"
                "\n";
        fprintf(stderr, str, prog, XSK_UMEM__DEFAULT_FRAME_SIZE,
                opt_batch_size, MIN_PKT_SIZE, MIN_PKT_SIZE,
@@ -964,7 +967,7 @@ static void parse_command_line(int argc, char **argv)
        opterr = 0;
 
        for (;;) {
-               c = getopt_long(argc, argv, "Frtli:q:pSNn:czf:muMd:b:C:s:P:xQaI:",
+               c = getopt_long(argc, argv, "Frtli:q:pSNn:czf:muMd:b:C:s:P:xQaI:B",
                                long_options, &option_index);
                if (c == -1)
                        break;
@@ -1062,7 +1065,9 @@ static void parse_command_line(int argc, char **argv)
                                fprintf(stderr, "ERROR: Failed to get irqs for %s\n", opt_irq_str);
                                usage(basename(argv[0]));
                        }
-
+                       break;
+               case 'B':
+                       opt_busy_poll = 1;
                        break;
                default:
                        usage(basename(argv[0]));
@@ -1131,7 +1136,7 @@ static inline void complete_tx_l2fwd(struct xsk_socket_info *xsk)
                while (ret != rcvd) {
                        if (ret < 0)
                                exit_with_error(-ret);
-                       if (xsk_ring_prod__needs_wakeup(&umem->fq)) {
+                       if (opt_busy_poll || xsk_ring_prod__needs_wakeup(&umem->fq)) {
                                xsk->app_stats.fill_fail_polls++;
                                recvfrom(xsk_socket__fd(xsk->xsk), NULL, 0, MSG_DONTWAIT, NULL,
                                         NULL);
@@ -1178,7 +1183,7 @@ static void rx_drop(struct xsk_socket_info *xsk)
 
        rcvd = xsk_ring_cons__peek(&xsk->rx, opt_batch_size, &idx_rx);
        if (!rcvd) {
-               if (xsk_ring_prod__needs_wakeup(&xsk->umem->fq)) {
+               if (opt_busy_poll || xsk_ring_prod__needs_wakeup(&xsk->umem->fq)) {
                        xsk->app_stats.rx_empty_polls++;
                        recvfrom(xsk_socket__fd(xsk->xsk), NULL, 0, MSG_DONTWAIT, NULL, NULL);
                }
@@ -1189,7 +1194,7 @@ static void rx_drop(struct xsk_socket_info *xsk)
        while (ret != rcvd) {
                if (ret < 0)
                        exit_with_error(-ret);
-               if (xsk_ring_prod__needs_wakeup(&xsk->umem->fq)) {
+               if (opt_busy_poll || xsk_ring_prod__needs_wakeup(&xsk->umem->fq)) {
                        xsk->app_stats.fill_fail_polls++;
                        recvfrom(xsk_socket__fd(xsk->xsk), NULL, 0, MSG_DONTWAIT, NULL, NULL);
                }
@@ -1341,7 +1346,7 @@ static void l2fwd(struct xsk_socket_info *xsk)
 
        rcvd = xsk_ring_cons__peek(&xsk->rx, opt_batch_size, &idx_rx);
        if (!rcvd) {
-               if (xsk_ring_prod__needs_wakeup(&xsk->umem->fq)) {
+               if (opt_busy_poll || xsk_ring_prod__needs_wakeup(&xsk->umem->fq)) {
                        xsk->app_stats.rx_empty_polls++;
                        recvfrom(xsk_socket__fd(xsk->xsk), NULL, 0, MSG_DONTWAIT, NULL, NULL);
                }
@@ -1354,7 +1359,7 @@ static void l2fwd(struct xsk_socket_info *xsk)
                if (ret < 0)
                        exit_with_error(-ret);
                complete_tx_l2fwd(xsk);
-               if (xsk_ring_prod__needs_wakeup(&xsk->tx)) {
+               if (opt_busy_poll || xsk_ring_prod__needs_wakeup(&xsk->tx)) {
                        xsk->app_stats.tx_wakeup_sendtos++;
                        kick_tx(xsk);
                }
@@ -1459,6 +1464,24 @@ static void enter_xsks_into_map(struct bpf_object *obj)
        }
 }
 
+static void apply_setsockopt(struct xsk_socket_info *xsk)
+{
+       int sock_opt;
+
+       if (!opt_busy_poll)
+               return;
+
+       sock_opt = 1;
+       if (setsockopt(xsk_socket__fd(xsk->xsk), SOL_SOCKET, SO_PREFER_BUSY_POLL,
+                      (void *)&sock_opt, sizeof(sock_opt)) < 0)
+               exit_with_error(errno);
+
+       sock_opt = 20;
+       if (setsockopt(xsk_socket__fd(xsk->xsk), SOL_SOCKET, SO_BUSY_POLL,
+                      (void *)&sock_opt, sizeof(sock_opt)) < 0)
+               exit_with_error(errno);
+}
+
 int main(int argc, char **argv)
 {
        struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
@@ -1500,6 +1523,9 @@ int main(int argc, char **argv)
        for (i = 0; i < opt_num_xsks; i++)
                xsks[num_socks++] = xsk_configure_socket(umem, rx, tx);
 
+       for (i = 0; i < opt_num_xsks; i++)
+               apply_setsockopt(xsks[i]);
+
        if (opt_bench == BENCH_TXONLY) {
                gen_eth_hdr_data();