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

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

[Stephen Hemminger]

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>
---
 lib/librte_mbuf/rte_mbuf.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
index 35df1c4c38a5..a964464bd598 100644
--- a/lib/librte_mbuf/rte_mbuf.c
+++ b/lib/librte_mbuf/rte_mbuf.c
@@ -473,11 +473,14 @@ 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,"
+		" offs=%u, refcnt=%u\n",
+		m, (uint64_t)m->buf_iova, (unsigned)m->buf_len,
+		(unsigned)m->data_off, (unsigned)rte_mbuf_refcnt_read(m));
+	fprintf(f, "  pkt_len=%u, ol_flags=%#"PRIx64","
+		" nb_segs=%u, in_port=%u, vlan_tci=%#x\n",
+		(unsigned)m->pkt_len, m->ol_flags,
+		(unsigned)m->nb_segs, (unsigned)m->port, (unsigned)m->vlan_tci);
 	nb_segs = m->nb_segs;
 
 	while (m && nb_segs != 0) {
-- 
2.20.1

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

[Morten Brørup]

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Stephen Hemminger
> Sent: Wednesday, November 20, 2019 6:41 PM
> 
> 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>
> ---
>  lib/librte_mbuf/rte_mbuf.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
> index 35df1c4c38a5..a964464bd598 100644
> --- a/lib/librte_mbuf/rte_mbuf.c
> +++ b/lib/librte_mbuf/rte_mbuf.c
> @@ -473,11 +473,14 @@ 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,"
> +		" offs=%u, refcnt=%u\n",
> +		m, (uint64_t)m->buf_iova, (unsigned)m->buf_len,
> +		(unsigned)m->data_off, (unsigned)rte_mbuf_refcnt_read(m));
> +	fprintf(f, "  pkt_len=%u, ol_flags=%#"PRIx64","
> +		" nb_segs=%u, in_port=%u, vlan_tci=%#x\n",
> +		(unsigned)m->pkt_len, m->ol_flags,
> +		(unsigned)m->nb_segs, (unsigned)m->port, (unsigned)m-
> >vlan_tci);

Are all these explicit type casts really needed? buf_iova is already uint64_t, buflen is uint16_t, data_off is uint16_t, rte_mbuf_refcnt_read() returns uint16_t, pkt_len is uint32_t, nb_segs is uint16_t, port is uint16_t, vlan_tci is uint16_t.

m->port is not only the input port anymore (ref. the mbuf documentation), so please change in_port=%u to port=%u.

For consistency with ol_flags and vlan_tci format, consider changing iova=% to iova=%#.

>  	nb_segs = m->nb_segs;
> 
>  	while (m && nb_segs != 0) {
> --
> 2.20.1
> 

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

[Stephen Hemminger]

On Thu, 21 Nov 2019 17:16:42 +0100
Morten Brørup <mb@smartsharesystems.com> wrote:

> Are all these explicit type casts really needed? buf_iova is already uint64_t, buflen is uint16_t, data_off is uint16_t, rte_mbuf_refcnt_read() returns uint16_t, pkt_len is uint32_t, nb_segs is uint16_t, port is uint16_t, vlan_tci is uint16_t.

Normally, they are not needed.
If you turn up some of the warning levels in Gcc, then yes.

> 
> m->port is not only the input port anymore (ref. the mbuf documentation), so please change in_port=%u to port=%u.

Makes sense, but since this in internal would rather keep existing
 to print the name of the field.

> 
> For consistency with ol_flags and vlan_tci format, consider changing iova=% to iova=%#.

good idea, personal preference is to always use %#x over %x

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

[Stephen Hemminger]

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

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

[Andrew Rybchenko]

On 11/21/19 9:30 PM, 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>

May be it would be a bit better to split cosmetic changes into
separate patch(es), but anyway

Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>

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

[Olivier Matz]

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

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

[Stephen Hemminger]

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.

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

[Olivier Matz]

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.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.

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.

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

[Stephen Hemminger]

On Fri, 27 Dec 2019 10:10:18 +0100
Olivier Matz <olivier.matz@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.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.  
> 
> 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

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

[Olivier Matz]

On Fri, Dec 27, 2019 at 09:05:07AM -0800, Stephen Hemminger wrote:
> On Fri, 27 Dec 2019 10:10:18 +0100
> Olivier Matz <olivier.matz@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.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.  
> > 
> > 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

PKT_RX_VLAN means that m->vlan_tci is valid, and this is what we
want here.

[dpdk-dev] [PATCH v3] mbuf: display more fields in dump

[Stephen Hemminger]

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>
Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>
---
v3 - only display vlan tci if offload flags say it is there
     display packet type
v2 - remove casts, change in_port to port
     the refcount and offset are property of per-segment

 lib/librte_mbuf/rte_mbuf.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
index 25eea1db259d..56a1a98a6c0c 100644
--- a/lib/librte_mbuf/rte_mbuf.c
+++ b/lib/librte_mbuf/rte_mbuf.c
@@ -675,18 +675,25 @@ 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",
+		m->pkt_len, m->ol_flags, m->nb_segs, m->port);
+
+	if (m->ol_flags & (PKT_RX_VLAN | PKT_TX_VLAN))
+		fprintf(f, ", vlan_tci=%u", m->vlan_tci);
+
+	fprintf(f, ", ptype=%#"PRIx32"\n", m->packet_type);
+
 	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

Re: [dpdk-dev] [PATCH v3] mbuf: display more fields in dump

[Olivier Matz]

On Wed, Jan 22, 2020 at 09:39:56AM -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>
> Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>

Acked-by: Olivier Matz <olivier.matz@6wind.com>

Re: [dpdk-dev] [PATCH v3] mbuf: display more fields in dump

[Thomas Monjalon]

06/02/2020 10:48, Olivier Matz:
> On Wed, Jan 22, 2020 at 09:39:56AM -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>
> > Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>
> 
> Acked-by: Olivier Matz <olivier.matz@6wind.com>

Applied, thanks