samples/bpf: Consider frame size in tx_only of xdpsock sample

Fix the tx_only micro-benchmark in xdpsock to take frame size into
consideration. It was hardcoded to the default value of frame_size
which is 4K. Changing this on the command line to 2K made half of the
packets illegal as they were outside the umem and were therefore
discarded by the kernel.

Fixes: 46738f73ea4f ("samples/bpf: add use of need_wakeup flag in xdpsock")
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/bpf/20210506124349.6666-1-magnus.karlsson@gmail.com

diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c
index aa696854be787e117a878fd9b8f4ab38af99fa8e..53e300f860bb4f4290307e8443fbf68f4d8cf7e0 100644 (file)
--- a/samples/bpf/xdpsock_user.c
+++ b/samples/bpf/xdpsock_user.c
@@ -1255,7 +1255,7 @@ static void tx_only(struct xsk_socket_info *xsk, u32 *frame_nb, int batch_size)
        for (i = 0; i < batch_size; i++) {
                struct xdp_desc *tx_desc = xsk_ring_prod__tx_desc(&xsk->tx,
                                                                  idx + i);
-               tx_desc->addr = (*frame_nb + i) << XSK_UMEM__DEFAULT_FRAME_SHIFT;
+               tx_desc->addr = (*frame_nb + i) * opt_xsk_frame_size;
                tx_desc->len = PKT_SIZE;
        }