Re: [dpdk-dev] [PATCH v2] mbuf: display more fields in dump

[Olivier Matz <olivier.matz@6wind.com>]

Hi,

On Thu, Nov 21, 2019 at 10:30:55AM -0800, Stephen Hemminger wrote:
> The rte_pktmbuf_dump should display offset, refcount, and vlan
> info since these are often useful during debugging.
> 
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
> v2 - remove casts, change in_port to port
>      the refcount and offset are property of per-segment
> 
>  lib/librte_mbuf/rte_mbuf.c | 17 ++++++++++-------
>  1 file changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
> index 35df1c4c38a5..4894d46628e3 100644
> --- a/lib/librte_mbuf/rte_mbuf.c
> +++ b/lib/librte_mbuf/rte_mbuf.c
> @@ -473,18 +473,21 @@ rte_pktmbuf_dump(FILE *f, const struct rte_mbuf *m, unsigned dump_len)
>  
>  	__rte_mbuf_sanity_check(m, 1);
>  
> -	fprintf(f, "dump mbuf at %p, iova=%"PRIx64", buf_len=%u\n",
> -	       m, (uint64_t)m->buf_iova, (unsigned)m->buf_len);
> -	fprintf(f, "  pkt_len=%"PRIu32", ol_flags=%"PRIx64", nb_segs=%u, "
> -	       "in_port=%u\n", m->pkt_len, m->ol_flags,
> -	       (unsigned)m->nb_segs, (unsigned)m->port);
> +	fprintf(f, "dump mbuf at %p, iova=%#"PRIx64", buf_len=%u\n",
> +		m, m->buf_iova, m->buf_len);
> +	fprintf(f,
> +		"  pkt_len=%u, ol_flags=%#"PRIx64", nb_segs=%u, port=%u, vlan_tci=%#x\n",
> +		m->pkt_len, m->ol_flags, m->nb_segs, m->port, m->vlan_tci);
> +
>  	nb_segs = m->nb_segs;
>  
>  	while (m && nb_segs != 0) {
>  		__rte_mbuf_sanity_check(m, 0);
>  
> -		fprintf(f, "  segment at %p, data=%p, data_len=%u\n",
> -			m, rte_pktmbuf_mtod(m, void *), (unsigned)m->data_len);
> +		fprintf(f, "  segment at %p, data=%p, len=%u, off=%u, refcnt=%u\n",
> +			m, rte_pktmbuf_mtod(m, void *),
> +			m->data_len, m->data_off, rte_mbuf_refcnt_read(m));
> +
>  		len = dump_len;
>  		if (len > m->data_len)
>  			len = m->data_len;
> -- 
> 2.20.1
> 

Thanks for this enhancement.

One comment however: I don't see why vlan_tci would be important than
packet type or rss tag. It is also a bit confusing to display a field
which can have a random value (if the vlan flag is not set in ol_flags).

I'd prefer to dump vlan_tci only if the flag is present. Later we could
add more fields with the same logic. What do you think?

Olivier