On Thu, Nov 19, 2020 at 9:33 AM Björn Töpel <bjorn.topel@xxxxxxxxx> wrote:
>
> From: Björn Töpel <bjorn.topel@xxxxxxxxx>
>
> Start using recvfrom() the l2fwd scenario, instead of poll() which is
> more expensive and need additional knobs for busy-polling.
>
> Signed-off-by: Björn Töpel <bjorn.topel@xxxxxxxxx>
> ---
> samples/bpf/xdpsock_user.c | 25 +++++++++++--------------
> 1 file changed, 11 insertions(+), 14 deletions(-)
Acked-by: Magnus Karlsson <magnus.karlsson@xxxxxxxxx>
> diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c
> index f90111b95b2e..24aa7511c4c8 100644
> --- a/samples/bpf/xdpsock_user.c
> +++ b/samples/bpf/xdpsock_user.c
> @@ -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 +1133,7 @@ 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 +1330,19 @@ 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 +1352,7 @@ 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 +1387,20 @@ static void l2fwd_all(void)
> struct pollfd fds[MAX_SOCKS] = {};
> int i, ret;
>
> - 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++)
> + for (i = 0; i < num_socks; i++) {
> + fds[i].fd = xsk_socket__fd(xsks[i]->xsk);
> + fds[i].events = POLLOUT | POLLIN;
> 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;
> --
> 2.27.0
>
