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

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 26 Dec 2019 17:15:39 +0100
Olivier Matz <olivier.matz@6wind.com> wrote:

> 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?

Because this is a debugging hook and easier to always display the value.
Thats all.