On Thu, 23 May 2019 19:56:47 +0900
Toshiaki Makita <makita.toshi...@lab.ntt.co.jp> wrote:

> This is introduced for admins to check what is happening on XDP_TX when
> bulk XDP_TX is in use.
> 
> Signed-off-by: Toshiaki Makita <makita.toshi...@lab.ntt.co.jp>
> ---
>  include/trace/events/xdp.h | 25 +++++++++++++++++++++++++
>  kernel/bpf/core.c          |  1 +
>  2 files changed, 26 insertions(+)
> 
> diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h
> index e95cb86..e06ea65 100644
> --- a/include/trace/events/xdp.h
> +++ b/include/trace/events/xdp.h
> @@ -50,6 +50,31 @@
>                 __entry->ifindex)
>  );
>  
> +TRACE_EVENT(xdp_bulk_tx,
> +

You are using this tracepoint like/instead of trace_xdp_devmap_xmit if
I understand correctly?  Or maybe the trace_xdp_redirect tracepoint.

The point is that is will be good if the tracepoints can share the
TP_STRUCT layout beginning, as it allows for attaching and reusing eBPF
code that is only interested in the top part of the struct.

I would also want to see some identifier, that trace programs can use
to group and corrolate these events, you do have ifindex, but most
other XDP tracepoints also have "prog_id".

> +     TP_PROTO(const struct net_device *dev,
> +              int sent, int drops, int err),
> +
> +     TP_ARGS(dev, sent, drops, err),
> +
> +     TP_STRUCT__entry(
> +             __field(int, ifindex)
> +             __field(int, drops)
> +             __field(int, sent)
> +             __field(int, err)
> +     ),

The xdp_redirect_template have:

        TP_STRUCT__entry(
                __field(int, prog_id)
                __field(u32, act)
                __field(int, ifindex)
                __field(int, err)
                __field(int, to_ifindex)
                __field(u32, map_id)
                __field(int, map_index)
        ),

And e.g. TRACE_EVENT xdp_exception have:

        TP_STRUCT__entry(
                __field(int, prog_id)
                __field(u32, act)
                __field(int, ifindex)
        ),


> +
> +     TP_fast_assign(
> +             __entry->ifindex        = dev->ifindex;
> +             __entry->drops          = drops;
> +             __entry->sent           = sent;
> +             __entry->err            = err;
> +     ),
> +
> +     TP_printk("ifindex=%d sent=%d drops=%d err=%d",
> +               __entry->ifindex, __entry->sent, __entry->drops, __entry->err)
> +);
> +
>  DECLARE_EVENT_CLASS(xdp_redirect_template,
>  
>       TP_PROTO(const struct net_device *dev,
> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> index 242a643..7687488 100644
> --- a/kernel/bpf/core.c
> +++ b/kernel/bpf/core.c
> @@ -2108,3 +2108,4 @@ int __weak skb_copy_bits(const struct sk_buff *skb, int 
> offset, void *to,
>  #include <linux/bpf_trace.h>
>  
>  EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
> +EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx);



-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer

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