Re: [PATCH 09/11] samples/bpf: add buffer recycling for unaligned chunks to xdpsock

["Björn Töpel" <bjorn.topel@gmail.com>]

On Thu, 20 Jun 2019 at 19:25, Kevin Laatz <kevin.laatz@intel.com> wrote:
>
> This patch adds buffer recycling support for unaligned buffers. Since we
> don't mask the addr to 2k at umem_teg in unaligned mode, we need to make
> sure we give back the correct, original addr to the fill queue. To do this,
> we need to mask the addr with the buffer size.
>
> To pass in a buffer size, use the --buf-size=n argument.
> NOTE: For xdpsock to work in aligned chunk mode, you still need to pass
> 'power of 2' buffer size.
>
> Signed-off-by: Kevin Laatz <kevin.laatz@intel.com>
> ---
>  samples/bpf/xdpsock_user.c | 71 +++++++++++++++++++++++++++-----------
>  1 file changed, 51 insertions(+), 20 deletions(-)
>
> diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c
> index e26f43382d01..7b4ce047deb2 100644
> --- a/samples/bpf/xdpsock_user.c
> +++ b/samples/bpf/xdpsock_user.c
> @@ -60,6 +60,10 @@ enum benchmark_type {
>         BENCH_L2FWD = 2,
>  };
>
> +#define LENGTH (256UL*1024*1024)
> +#define ADDR (void *)(0x0UL)
> +#define SHMAT_FLAGS (0)

Not used.

> +
>  static enum benchmark_type opt_bench = BENCH_RXDROP;
>  static u32 opt_xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
>  static const char *opt_if = "";
> @@ -67,6 +71,7 @@ static int opt_ifindex;
>  static int opt_queue;
>  static int opt_poll;
>  static int opt_interval = 1;
> +static u64 opt_buffer_size = XSK_UMEM__DEFAULT_FRAME_SIZE;
>  static u32 opt_umem_flags;
>  static int opt_unaligned_chunks;
>  static u32 opt_xdp_bind_flags;
> @@ -287,7 +292,7 @@ static struct xsk_umem_info *xsk_configure_umem(void *buffer, u64 size)
>
>         umem_cfg.fill_size = XSK_RING_PROD__DEFAULT_NUM_DESCS;
>         umem_cfg.comp_size = XSK_RING_CONS__DEFAULT_NUM_DESCS;
> -       umem_cfg.frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE;
> +       umem_cfg.frame_size = opt_buffer_size;
>         umem_cfg.frame_headroom = XSK_UMEM__DEFAULT_FRAME_HEADROOM;
>         umem_cfg.flags = opt_umem_flags;
>
> @@ -334,8 +339,8 @@ static struct xsk_socket_info *xsk_configure_socket(struct xsk_umem_info *umem)
>                 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)
> +                    opt_buffer_size;
> +            i += opt_buffer_size)
>                 *xsk_ring_prod__fill_addr(&xsk->umem->fq, idx++) = i;
>         xsk_ring_prod__submit(&xsk->umem->fq,
>                               XSK_RING_PROD__DEFAULT_NUM_DESCS);
> @@ -356,6 +361,7 @@ static struct option long_options[] = {
>         {"zero-copy", no_argument, 0, 'z'},
>         {"copy", no_argument, 0, 'c'},
>         {"unaligned", no_argument, 0, 'u'},
> +       {"buf-size", required_argument, 0, 'b'},
>         {0, 0, 0, 0}
>  };
>
> @@ -376,6 +382,7 @@ static void usage(const char *prog)
>                 "  -z, --zero-copy      Force zero-copy mode.\n"
>                 "  -c, --copy           Force copy mode.\n"
>                 "  -u, --unaligned      Enable unaligned chunk placement\n"
> +               "  -b, --buf-size=n     Specify the buffer size to use\n"
>                 "\n";
>         fprintf(stderr, str, prog);
>         exit(EXIT_FAILURE);
> @@ -388,7 +395,7 @@ static void parse_command_line(int argc, char **argv)
>         opterr = 0;
>
>         for (;;) {
> -               c = getopt_long(argc, argv, "Frtli:q:psSNn:czu", long_options,
> +               c = getopt_long(argc, argv, "Frtli:q:psSNn:czub", long_options,
>                                 &option_index);
>                 if (c == -1)
>                         break;
> @@ -432,6 +439,9 @@ static void parse_command_line(int argc, char **argv)
>                         opt_umem_flags |= XDP_UMEM_UNALIGNED_CHUNKS;
>                         opt_unaligned_chunks = 1;
>                         break;
> +               case 'b':
> +                       opt_buffer_size = atoi(optarg);
> +                       break;
>                 case 'F':
>                         opt_xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
>                         break;
> @@ -483,13 +493,22 @@ static inline void complete_tx_l2fwd(struct xsk_socket_info *xsk)
>                 while (ret != rcvd) {
>                         if (ret < 0)
>                                 exit_with_error(-ret);
> -                       ret = xsk_ring_prod__reserve(&xsk->umem->fq, rcvd,
> -                                                    &idx_fq);
> +                       ret = xsk_ring_prod__reserve(&xsk->umem->fq, rcvd, &idx_fq);
> +               }
> +
> +               if (opt_umem_flags & XDP_UMEM_UNALIGNED_CHUNKS) {
> +                       for (i = 0; i < rcvd; i++) {
> +                               u64 comp_addr = *xsk_ring_cons__comp_addr(&xsk->umem->cq,
> +                                               idx_cq++);
> +                               u64 masked_comp = (comp_addr & ~((u64)opt_buffer_size-1));
> +                               *xsk_ring_prod__fill_addr(&xsk->umem->fq, idx_fq++) =
> +                                               masked_comp;
> +                       }
> +               } else {
> +                       for (i = 0; i < rcvd; i++)
> +                               *xsk_ring_prod__fill_addr(&xsk->umem->fq, idx_fq++) =
> +                                               *xsk_ring_cons__comp_addr(&xsk->umem->cq, idx_cq++);
>                 }
> -               for (i = 0; i < rcvd; i++)
> -                       *xsk_ring_prod__fill_addr(&xsk->umem->fq, idx_fq++) =
> -                               *xsk_ring_cons__comp_addr(&xsk->umem->cq,
> -                                                         idx_cq++);
>
>                 xsk_ring_prod__submit(&xsk->umem->fq, rcvd);
>                 xsk_ring_cons__release(&xsk->umem->cq, rcvd);
> @@ -533,13 +552,25 @@ static void rx_drop(struct xsk_socket_info *xsk)
>                 ret = xsk_ring_prod__reserve(&xsk->umem->fq, rcvd, &idx_fq);
>         }
>
> -       for (i = 0; i < rcvd; i++) {
> -               u64 addr = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx)->addr;
> -               u32 len = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx++)->len;
> -               char *pkt = xsk_umem__get_data(xsk->umem->buffer, addr);
> +       if (opt_umem_flags & XDP_UMEM_UNALIGNED_CHUNKS) {
> +               for (i = 0; i < rcvd; i++) {
> +                       u64 addr = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx)->addr;
> +                       u32 len = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx++)->len;
> +                       char *pkt = xsk_umem__get_data(xsk->umem->buffer, addr);
> +                       u64 masked_addr = (addr & ~((u64)opt_buffer_size-1));
> +
> +                       hex_dump(pkt, len, addr);
> +                       *xsk_ring_prod__fill_addr(&xsk->umem->fq, idx_fq++) = masked_addr;
> +               }
> +       } else {
> +               for (i = 0; i < rcvd; i++) {
> +                       u64 addr = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx)->addr;
> +                       u32 len = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx++)->len;
> +                       char *pkt = xsk_umem__get_data(xsk->umem->buffer, addr);
>
> -               hex_dump(pkt, len, addr);
> -               *xsk_ring_prod__fill_addr(&xsk->umem->fq, idx_fq++) = addr;
> +                       hex_dump(pkt, len, addr);
> +                       *xsk_ring_prod__fill_addr(&xsk->umem->fq, idx_fq++) = addr;
> +               }
>         }
>
>         xsk_ring_prod__submit(&xsk->umem->fq, rcvd);
> @@ -677,20 +708,20 @@ int main(int argc, char **argv)
>         }
>
>         ret = posix_memalign(&bufs, getpagesize(), /* PAGE_SIZE aligned */
> -                            NUM_FRAMES * XSK_UMEM__DEFAULT_FRAME_SIZE);
> +                            NUM_FRAMES * opt_buffer_size);
>         if (ret)
>                 exit_with_error(ret);
>
>         /* Create sockets... */
>         umem = xsk_configure_umem(bufs,
> -                                 NUM_FRAMES * XSK_UMEM__DEFAULT_FRAME_SIZE);
> +                                 NUM_FRAMES * opt_buffer_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)
> +               for (i = 0; i < NUM_FRAMES * opt_buffer_size;
> +                    i += opt_buffer_size)
>                         (void)gen_eth_frame(umem, i);
>         }
>
> --
> 2.17.1
>