Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Keshav Gupta]

Hi Federico and all
 I will work on this Rohitha's patch to take it forward.

Thanks
Keshav

-Original Message-
From: ovs-dev-boun...@openvswitch.org [mailto:ovs-dev-boun...@openvswitch.org] 
On Behalf Of Federico Iezzi
Sent: Tuesday, July 24, 2018 1:23 PM
To: ian.sto...@intel.com
Cc: d...@openvswitch.org
Subject: Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

Hi all,

It seems Rohith Basavaraja email has been disabled.
I believe it's too late for someone else to pick up Rohith's work, right?

Federico

On Mon, 11 Jun 2018 at 10:33, Stokes, Ian  wrote:

> > I'm very sorry for double posting.
> > I believe this patch would represent a major feature in term of 
> > OVS's usability.
> > Has anyone got any time for reviewing it?
> >
>
> I'm planning to look at it this week.
>
> Thanks
> Ian
>
> > Thanks,
> > Federico
> >
> > On 6 June 2018 at 17:37, Jan Scheurich 
> wrote:
> >
> > > The user-space part for packet drop stats should be generic and 
> > > work with any dpif datapath.
> > > So, if someone implemented the equivalent drop stats functionality 
> > > in the kernel datapath that would be very welcome.
> > > We in Ericsson cannot do that currently due to license restrictions.
> > >
> > > Regards, Jan
> > >
> > > > -Original Message-
> > > > From: ovs-dev-boun...@openvswitch.org 
> > > > 
> > > On Behalf Of Rohith Basavaraja
> > > > Sent: Friday, 25 May, 2018 07:37
> > > > To: Ben Pfaff 
> > > > Cc: d...@openvswitch.org
> > > > Subject: Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics 
> > > > in
> OVS.
> > > >
> > > > Thanks Ben for the clarification. Yes this new stuff is used 
> > > > only in the DPDK datapath and it’s not used in the kernel datapath.
> > > >
> > > > Thanks
> > > > Rohith
> > > >
> > > > On 25/05/18, 2:52 AM, "Ben Pfaff"  wrote:
> > > >
> > > > On Thu, May 24, 2018 at 02:19:06AM +, Rohith Basavaraja
> wrote:
> > > > > Only  changes in
> > > > > datapath/linux/compat/include/linux/openvswitch.h
> > > > > are related to OvS Kernel module.
> > > >
> > > > On a second look, I see that the new stuff here is only for 
> > > > the
> > DPDK
> > > > datapath.  If you don't intend to add this feature to the kernel
> > > > datapath, there should be no problem.  Never mind.
> > > >
> > > >
> > > > ___
> > > > dev mailing list
> > > > d...@openvswitch.org
> > > > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> > > ___
> > > dev mailing list
> > > d...@openvswitch.org
> > > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> > >
> > ___
> > dev mailing list
> > d...@openvswitch.org
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>
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Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Federico Iezzi]

Hi all,

It seems Rohith Basavaraja email has been disabled.
I believe it's too late for someone else to pick up Rohith's work, right?

Federico

On Mon, 11 Jun 2018 at 10:33, Stokes, Ian  wrote:

> > I'm very sorry for double posting.
> > I believe this patch would represent a major feature in term of OVS's
> > usability.
> > Has anyone got any time for reviewing it?
> >
>
> I'm planning to look at it this week.
>
> Thanks
> Ian
>
> > Thanks,
> > Federico
> >
> > On 6 June 2018 at 17:37, Jan Scheurich 
> wrote:
> >
> > > The user-space part for packet drop stats should be generic and work
> > > with any dpif datapath.
> > > So, if someone implemented the equivalent drop stats functionality in
> > > the kernel datapath that would be very welcome.
> > > We in Ericsson cannot do that currently due to license restrictions.
> > >
> > > Regards, Jan
> > >
> > > > -Original Message-
> > > > From: ovs-dev-boun...@openvswitch.org
> > > > 
> > > On Behalf Of Rohith Basavaraja
> > > > Sent: Friday, 25 May, 2018 07:37
> > > > To: Ben Pfaff 
> > > > Cc: d...@openvswitch.org
> > > > Subject: Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in
> OVS.
> > > >
> > > > Thanks Ben for the clarification. Yes this new stuff is used only in
> > > > the DPDK datapath and it’s not used in the kernel datapath.
> > > >
> > > > Thanks
> > > > Rohith
> > > >
> > > > On 25/05/18, 2:52 AM, "Ben Pfaff"  wrote:
> > > >
> > > > On Thu, May 24, 2018 at 02:19:06AM +, Rohith Basavaraja
> wrote:
> > > > > Only  changes in
> > > > > datapath/linux/compat/include/linux/openvswitch.h
> > > > > are related to OvS Kernel module.
> > > >
> > > > On a second look, I see that the new stuff here is only for the
> > DPDK
> > > > datapath.  If you don't intend to add this feature to the kernel
> > > > datapath, there should be no problem.  Never mind.
> > > >
> > > >
> > > > ___
> > > > dev mailing list
> > > > d...@openvswitch.org
> > > > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> > > ___
> > > dev mailing list
> > > d...@openvswitch.org
> > > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> > >
> > ___
> > dev mailing list
> > d...@openvswitch.org
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>
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Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Federico Iezzi]

I see it doesn't merge anymore, I have very little hopes to see it in with
2.10 ...

On Mon, 11 Jun 2018 at 10:33, Stokes, Ian  wrote:

> > I'm very sorry for double posting.
> > I believe this patch would represent a major feature in term of OVS's
> > usability.
> > Has anyone got any time for reviewing it?
> >
>
> I'm planning to look at it this week.
>
> Thanks
> Ian
>
> > Thanks,
> > Federico
> >
> > On 6 June 2018 at 17:37, Jan Scheurich 
> wrote:
> >
> > > The user-space part for packet drop stats should be generic and work
> > > with any dpif datapath.
> > > So, if someone implemented the equivalent drop stats functionality in
> > > the kernel datapath that would be very welcome.
> > > We in Ericsson cannot do that currently due to license restrictions.
> > >
> > > Regards, Jan
> > >
> > > > -Original Message-
> > > > From: ovs-dev-boun...@openvswitch.org
> > > > 
> > > On Behalf Of Rohith Basavaraja
> > > > Sent: Friday, 25 May, 2018 07:37
> > > > To: Ben Pfaff 
> > > > Cc: d...@openvswitch.org
> > > > Subject: Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in
> OVS.
> > > >
> > > > Thanks Ben for the clarification. Yes this new stuff is used only in
> > > > the DPDK datapath and it’s not used in the kernel datapath.
> > > >
> > > > Thanks
> > > > Rohith
> > > >
> > > > On 25/05/18, 2:52 AM, "Ben Pfaff"  wrote:
> > > >
> > > > On Thu, May 24, 2018 at 02:19:06AM +, Rohith Basavaraja
> wrote:
> > > > > Only  changes in
> > > > > datapath/linux/compat/include/linux/openvswitch.h
> > > > > are related to OvS Kernel module.
> > > >
> > > > On a second look, I see that the new stuff here is only for the
> > DPDK
> > > > datapath.  If you don't intend to add this feature to the kernel
> > > > datapath, there should be no problem.  Never mind.
> > > >
> > > >
> > > > ___
> > > > dev mailing list
> > > > d...@openvswitch.org
> > > > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> > > ___
> > > dev mailing list
> > > d...@openvswitch.org
> > > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> > >
> > ___
> > dev mailing list
> > d...@openvswitch.org
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>
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Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Stokes, Ian]

> I'm very sorry for double posting.
> I believe this patch would represent a major feature in term of OVS's
> usability.
> Has anyone got any time for reviewing it?
> 

I'm planning to look at it this week.

Thanks
Ian

> Thanks,
> Federico
> 
> On 6 June 2018 at 17:37, Jan Scheurich  wrote:
> 
> > The user-space part for packet drop stats should be generic and work
> > with any dpif datapath.
> > So, if someone implemented the equivalent drop stats functionality in
> > the kernel datapath that would be very welcome.
> > We in Ericsson cannot do that currently due to license restrictions.
> >
> > Regards, Jan
> >
> > > -Original Message-
> > > From: ovs-dev-boun...@openvswitch.org
> > > 
> > On Behalf Of Rohith Basavaraja
> > > Sent: Friday, 25 May, 2018 07:37
> > > To: Ben Pfaff 
> > > Cc: d...@openvswitch.org
> > > Subject: Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.
> > >
> > > Thanks Ben for the clarification. Yes this new stuff is used only in
> > > the DPDK datapath and it’s not used in the kernel datapath.
> > >
> > > Thanks
> > > Rohith
> > >
> > > On 25/05/18, 2:52 AM, "Ben Pfaff"  wrote:
> > >
> > > On Thu, May 24, 2018 at 02:19:06AM +, Rohith Basavaraja wrote:
> > > > Only  changes in
> > > > datapath/linux/compat/include/linux/openvswitch.h
> > > > are related to OvS Kernel module.
> > >
> > > On a second look, I see that the new stuff here is only for the
> DPDK
> > > datapath.  If you don't intend to add this feature to the kernel
> > > datapath, there should be no problem.  Never mind.
> > >
> > >
> > > ___
> > > dev mailing list
> > > d...@openvswitch.org
> > > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> > ___
> > dev mailing list
> > d...@openvswitch.org
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> >
> ___
> dev mailing list
> d...@openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
___
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Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Federico Iezzi]

I'm very sorry for double posting.
I believe this patch would represent a major feature in term of OVS's
usability.
Has anyone got any time for reviewing it?

Thanks,
Federico

On 6 June 2018 at 17:37, Jan Scheurich  wrote:

> The user-space part for packet drop stats should be generic and work with
> any dpif datapath.
> So, if someone implemented the equivalent drop stats functionality in the
> kernel datapath that would be very welcome.
> We in Ericsson cannot do that currently due to license restrictions.
>
> Regards, Jan
>
> > -Original Message-
> > From: ovs-dev-boun...@openvswitch.org 
> On Behalf Of Rohith Basavaraja
> > Sent: Friday, 25 May, 2018 07:37
> > To: Ben Pfaff 
> > Cc: d...@openvswitch.org
> > Subject: Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.
> >
> > Thanks Ben for the clarification. Yes this new stuff is used only in the
> > DPDK datapath and it’s not used in the kernel datapath.
> >
> > Thanks
> > Rohith
> >
> > On 25/05/18, 2:52 AM, "Ben Pfaff"  wrote:
> >
> > On Thu, May 24, 2018 at 02:19:06AM +, Rohith Basavaraja wrote:
> > > Only  changes in
> > > datapath/linux/compat/include/linux/openvswitch.h
> > > are related to OvS Kernel module.
> >
> > On a second look, I see that the new stuff here is only for the DPDK
> > datapath.  If you don't intend to add this feature to the kernel
> > datapath, there should be no problem.  Never mind.
> >
> >
> > ___
> > dev mailing list
> > d...@openvswitch.org
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> ___
> dev mailing list
> d...@openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>
___
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d...@openvswitch.org
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Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Jan Scheurich]

The user-space part for packet drop stats should be generic and work with any 
dpif datapath. 
So, if someone implemented the equivalent drop stats functionality in the 
kernel datapath that would be very welcome.
We in Ericsson cannot do that currently due to license restrictions.

Regards, Jan

> -Original Message-
> From: ovs-dev-boun...@openvswitch.org  On 
> Behalf Of Rohith Basavaraja
> Sent: Friday, 25 May, 2018 07:37
> To: Ben Pfaff 
> Cc: d...@openvswitch.org
> Subject: Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.
> 
> Thanks Ben for the clarification. Yes this new stuff is used only in the
> DPDK datapath and it’s not used in the kernel datapath.
> 
> Thanks
> Rohith
> 
> On 25/05/18, 2:52 AM, "Ben Pfaff"  wrote:
> 
> On Thu, May 24, 2018 at 02:19:06AM +, Rohith Basavaraja wrote:
> > Only  changes in
> > datapath/linux/compat/include/linux/openvswitch.h
> > are related to OvS Kernel module.
> 
> On a second look, I see that the new stuff here is only for the DPDK
> datapath.  If you don't intend to add this feature to the kernel
> datapath, there should be no problem.  Never mind.
> 
> 
> ___
> dev mailing list
> d...@openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
___
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Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Federico Iezzi]

Hello everyone,

May I ask to provide some (even brief) documentation about each specific
drop counter?
That would really help understanding why a specific drop is happening.

Thanks,
Federico

On 25 May 2018 at 07:44, Rohith Basavaraja 
wrote:

> Hi Greg,
>
> Thanks a lot for sharing the info.
> Ben clarified that it should be ok if this new stuff is used only in the
> DPDK datapath and it’s not used in the kernel datapath.
>
> Thanks
> Rohith
>
>
>
> On 24/05/18, 9:05 PM, "Gregory Rose"  wrote:
>
> On 5/23/2018 7:19 PM, Rohith Basavaraja wrote:
> > Hi Ben,
> >
> > Only  changes in
> > datapath/linux/compat/include/linux/openvswitch.h
> > are related to OvS Kernel module.
> >
> > The changes in openvswitch.h are not upstreamed yet.
> > Can you please let me know the procedure for submitting the
> > Changes for OvS Kernel Module?.
> >
> > In the meanwhile can I get code review feedback for the changes,
> while I
> > Figure out how to commit changes in datapath/linux/compat/include/
> linux/openvswitch.h.
> >
> > Thanks
> > Rohith
>
> You need to submit changes to openvswitch.h to the Linux network mail
> list.
>
> https://www.kernel.org/doc/Documentation/networking/netdev-FAQ.txt
>
> After acceptance upstream we can then pull in the change.
>
> And this might help as well.
>
> https://www.kernel.org/doc/html/v4.16/process/submitting-patches.html
>
> Thanks,
>
> - Greg
>
> >
> >
> > On 24/05/18, 2:03 AM, "Ben Pfaff"  wrote:
> >
> >  I see that this adds code to the OVS kernel module.  Are these
> changes
> >  upstream already in Linux?  Usually we use an "upstream first"
> >  philosophy regarding the kernel module.
> >
> >
> > ___
> > dev mailing list
> > d...@openvswitch.org
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>
>
>
> ___
> dev mailing list
> d...@openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>
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Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Rohith Basavaraja]

Hi Greg,

Thanks a lot for sharing the info.
Ben clarified that it should be ok if this new stuff is used only in the
DPDK datapath and it’s not used in the kernel datapath.

Thanks
Rohith



On 24/05/18, 9:05 PM, "Gregory Rose"  wrote:

On 5/23/2018 7:19 PM, Rohith Basavaraja wrote:
> Hi Ben,
>
> Only  changes in
> datapath/linux/compat/include/linux/openvswitch.h
> are related to OvS Kernel module.
>
> The changes in openvswitch.h are not upstreamed yet.
> Can you please let me know the procedure for submitting the
> Changes for OvS Kernel Module?.
>
> In the meanwhile can I get code review feedback for the changes, while I
> Figure out how to commit changes in 
datapath/linux/compat/include/linux/openvswitch.h.
>
> Thanks
> Rohith

You need to submit changes to openvswitch.h to the Linux network mail list.

https://www.kernel.org/doc/Documentation/networking/netdev-FAQ.txt

After acceptance upstream we can then pull in the change.

And this might help as well.

https://www.kernel.org/doc/html/v4.16/process/submitting-patches.html

Thanks,

- Greg

>
>
> On 24/05/18, 2:03 AM, "Ben Pfaff"  wrote:
>
>  I see that this adds code to the OVS kernel module.  Are these 
changes
>  upstream already in Linux?  Usually we use an "upstream first"
>  philosophy regarding the kernel module.
>  
>
> ___
> dev mailing list
> d...@openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev



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Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Rohith Basavaraja]

Thanks Ben for the clarification. Yes this new stuff is used only in the
DPDK datapath and it’s not used in the kernel datapath.

Thanks
Rohith

On 25/05/18, 2:52 AM, "Ben Pfaff"  wrote:

On Thu, May 24, 2018 at 02:19:06AM +, Rohith Basavaraja wrote:
> Only  changes in 
> datapath/linux/compat/include/linux/openvswitch.h
> are related to OvS Kernel module.  

On a second look, I see that the new stuff here is only for the DPDK
datapath.  If you don't intend to add this feature to the kernel
datapath, there should be no problem.  Never mind.


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Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Ben Pfaff]

On Thu, May 24, 2018 at 02:19:06AM +, Rohith Basavaraja wrote:
> Only  changes in 
> datapath/linux/compat/include/linux/openvswitch.h
> are related to OvS Kernel module.  

On a second look, I see that the new stuff here is only for the DPDK
datapath.  If you don't intend to add this feature to the kernel
datapath, there should be no problem.  Never mind.
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Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Gregory Rose]

On 5/23/2018 7:19 PM, Rohith Basavaraja wrote:

Hi Ben,

Only  changes in
datapath/linux/compat/include/linux/openvswitch.h
are related to OvS Kernel module.

The changes in openvswitch.h are not upstreamed yet.
Can you please let me know the procedure for submitting the
Changes for OvS Kernel Module?.

In the meanwhile can I get code review feedback for the changes, while I
Figure out how to commit changes in 
datapath/linux/compat/include/linux/openvswitch.h.

Thanks
Rohith


You need to submit changes to openvswitch.h to the Linux network mail list.

https://www.kernel.org/doc/Documentation/networking/netdev-FAQ.txt

After acceptance upstream we can then pull in the change.

And this might help as well.

https://www.kernel.org/doc/html/v4.16/process/submitting-patches.html

Thanks,

- Greg




On 24/05/18, 2:03 AM, "Ben Pfaff"  wrote:

 I see that this adds code to the OVS kernel module.  Are these changes
 upstream already in Linux?  Usually we use an "upstream first"
 philosophy regarding the kernel module.
 


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Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Rohith Basavaraja]

Hi Ben,

Only  changes in 
datapath/linux/compat/include/linux/openvswitch.h
are related to OvS Kernel module.  

The changes in openvswitch.h are not upstreamed yet.
Can you please let me know the procedure for submitting the
Changes for OvS Kernel Module?.

In the meanwhile can I get code review feedback for the changes, while I 
Figure out how to commit changes in 
datapath/linux/compat/include/linux/openvswitch.h.

Thanks
Rohith 


On 24/05/18, 2:03 AM, "Ben Pfaff"  wrote:

I see that this adds code to the OVS kernel module.  Are these changes
upstream already in Linux?  Usually we use an "upstream first"
philosophy regarding the kernel module.


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Re: [ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Ben Pfaff]

I see that this adds code to the OVS kernel module.  Are these changes
upstream already in Linux?  Usually we use an "upstream first"
philosophy regarding the kernel module.
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[ovs-dev] [PATCH] Improved Packet Drop Statistics in OVS.

[Rohith Basavaraja]

Currently OVS maintains explicit packet drop/error counters only on port
level. Packets that are dropped as part of normal OpenFlow processing are
counted in flow stats of “drop” flows or as table misses in table stats.
These can only be interpreted by controllers that know the semantics of
the configured OpenFlow pipeline. Without that knowledge, it is impossible
for an OVS user to obtain e.g. the total number of packets dropped due to
OpenFlow rules.

Furthermore, there are numerous other reasons for which packets can be
dropped by OVS slow path that are not related to the OpenFlow pipeline.
The generated datapath flow entries include a drop action to avoid further
expensive upcalls to the slow path, but subsequent packets dropped by the
datapath are not accounted anywhere.

Finally, the datapath itself drops packets in certain error situations.
Also, these drops are today not accounted for.

This makes it difficult for OVS users to monitor packet drop in an OVS
instance and to alert a management system in case of a unexpected increase
of such drops. Also OVS trouble-shooters face difficulties in analysing
packet drops.

With this patch we implement following changes to address the issues
mentioned above.

1. Account and categorize all the packet drops in OVS.
2. Account & classify “drop” action packet drops according to the drop
   reason.
3. Identify and account all the silent packet drop scenarios.
4. Have new cli command to display consolidated packet drop output
5. Modified ovs-appctl dpcls/dump-flows and ovs-appctl dpif/dump-flows
   to print drop reason along with drop action

A detailed presentation on this was presented at OvS conference 2017 and
link for the corresponding presentation is available at:

https://www.slideshare.net/LF_OpenvSwitch/lfovs17troubleshooting-the-data-plane-in-ovs-82280329

In the subsequent commits plan to add the corresponding tests.

Sample ovs-appctl dpcls/dump-flows & ovs-appctl dpif/dump-flows
displaying drop reason along with drop action.
---

$ ovs-appctl dpctl/dump-flows netdev@ovs-netdev
flow-dump from pmd on cpu core: 0

recirc_id(0),in_port(5),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), 
packets:12, bytes:1176, used:0.884s, actions:drop:recursion too deep

$ ovs-appctl dpif/dump-flows br-int

recirc_id(0),in_port(5),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), 
packets:25, bytes:2450, used:5.008s, actions:drop:recursion too deep
recirc_id(0),in_port(5),packet_type(ns=0,id=0),eth_type(0x0806), packets:7, 
bytes:294, used:0.009s, actions:drop:recursion too deep

Sample drop stats summary output.
-
$ ovs-appctl dpif/show-drop-stats
netdev:
rx-drops:0
dataplane-processing-drops  :59
 drop action:59
 upcall drops   :0
 dp error drops :0
tx-drops:0

Sample detailed drop stats output.
-
$ ovs-appctl dpif/show-drop-stats --detail
netdev:
rx-drops:
[IDX]   Drop ReasonPackets
---  - 
0   interface & policer0
1   parsing error/invalid packet   0
dataplane-processing-drops:
"drop" action:
2   pipeline drop  0
3   bridge not found   0
4   recursion too deep 68
5   too many resubmits 0
6   stack too deep 0
7   no recirculation context   0
8   recirculation conflict 0
9   too many mpls labels   0
10  invalid tunnel metadata0
11  unsupported packet type0
12  ecn mismatch at tunnel decapsulation   0
13  forwarding disabled (stp/rstp) 0
upcall drops:
14  upcall lock contention drop0
15  upcall error drops 0
dp drops:
16  tunnel pop action errors   0
17  tunnel push action errors  0
18  nsh decap errors   0
19  recirculation errors   0
20  sampling error 0
21  meter drop 0
22  user space action error0
23  invalid port   0
24  invalid tunnel port0
tx-drops:
25  interface & policer0

Drop stats clear command.
-
$ ovs-appctl dpif/clear-drop-stats
$