On Fri, 27 Dec 2019 10:10:18 +0100
Olivier Matz <olivier.m...@6wind.com> wrote:
> Hi,
>
> On Thu, Dec 26, 2019 at 08:58:51AM -0800, Stephen Hemminger wrote:
> > On Thu, 26 Dec 2019 17:15:39 +0100
> > Olivier Matz <olivier.m...@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 <step...@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.
>
> This is precisely because it is a debug hook that I find dangerous to
> display a wrong value. As the mbuf are recycled, a mbuf that does not
> have a vlan_tci can display its previous value, which may look valid.
>
> What about simply doing this?
>
> fprintf(f,
> " pkt_len=%u, ol_flags=%#"PRIx64", nb_segs=%u, port=%u",
> m->pkt_len, m->ol_flags, m->nb_segs, m->port);
> if (m->ol_flags & PKT_RX_VLAN)
> fprintf(f, ", vlan_tci=%#x", m->vlan_tci);
> fprintf(f, "\n");
>
> If you want I can submit an updated version of your patch
The right flags are more complex, you need to deal with TX vlan.
And PKT_RX_VLAN means "this is a vlan packet" it doesn't mean
vlan tag is stripped into TCI. That is PKT_RX_VLAN_STRIPPED
