[ovs-dev] [PATCH] Detailed packet drop statistics per dpdk and vhostuser ports

[Sriram Vatala]

Hi Ilya,

Sorry for the late reply. Yes, whatever you suggested is doable.  As of now ovs-bugtool has only dpctl/show command and i think we need to add this command "ovs-vsctl get interface" to ovs-bugtool.  I will float the updated patch ASAP.

Thanks & Regards,
Sriram.

-----Original Message-----
From: Ilya Maximets <i.maximets at samsung.com> 
Sent: 07 June 2019 20:08
To: Sriram Vatala <sriram.v at altencalsoftlabs.com>; ovs-dev at openvswitch.org
Cc: Stokes, Ian <ian.stokes at intel.com>; Kevin Traynor <ktraynor at redhat.com>
Subject: Re: [ovs-dev] [PATCH] Detailed packet drop statistics per dpdk and vhostuser ports

On 07.06.2019 17:28, Ilya Maximets wrote:
> On 07.06.2019 15:39, Sriram Vatala wrote:
>> OVS may be unable to transmit packets for multiple reasons and today 
>> there is a single counter to track packets dropped due to any of 
>> those reasons. The most common reason is that a VM is unable to read 
>> packets fast enough causing the vhostuser port transmit queue on the 
>> OVS side to become full. This manifests as a problem with VNFs not 
>> receiving all packets. Having a separate drop counter to track 
>> packets dropped because the transmit queue is full will clearly 
>> indicate that the problem is on the VM side and not in OVS. Similarly 
>> maintaining separate counters for all possible drops helps in 
>> indicating sensible cause for packet drops.
>>
>> This patch adds counters to track packets dropped due to all possible 
>> reasons and display them when "--details" optional flag is passed  to 
>> “ovs-appctl dpctl/show -s” . The detailed stats will be available for 
>> both dpdk and vhostuser ports.
>>
>> cmd Usage : "ovs-appctl dpctl/show -s --details" (OR)
>>             "ovs-appctl dpctl/show --statistics --details"
>>
>> Following are the details of the new counters :
>>
>> queue_full : These are the packets dropped due to Transmit queue overrun.
>> mtu_exceeded : These are the packets dropped due to MTU mismatch.
>>                (i.e Pkt len > Max Dev MTU) qos : These are the 
>> packets dropped due to transmission/reception rate
>>       exceeding the configured Egress/Ingress policer rate on the interface.
>>
>> Signed-off-by: Sriram Vatala <sriram.v at altencalsoftlabs.com>
>> ---
>>  include/openvswitch/netdev.h |  8 ++++++++
>>  lib/dpctl.c                  | 26 ++++++++++++++++++++++-
>>  lib/dpctl.h                  |  5 +++++
>>  lib/dpctl.man                |  8 ++++++--
>>  lib/netdev-dpdk.c            | 49 +++++++++++++++++++++++++++++++++++++-------
>>  5 files changed, 86 insertions(+), 10 deletions(-)
> 
> Hi, Sriram.
> Thanks for working on OVS improvement.
> 
> I didn't look at the code yet, but one thing I wanted to mention is 
> that dpctl interface seems redundant here. It provides only basic 
> statistics, but you're adding some really specific stuff. Also, full 
> port stats are always available via db interface:
> 
>   ovs-vsctl get interface <iface> statistics
> 
> Your new stats counters will be there automatically.

Only need to add a few lines to '#define IFACE_STATS' in vswitchd/bridge.c.

> I think, it's better to drop dpctl parts of this patch.
> 
> What do you think?
> 
> Best regards, Ilya Maximets.	
> 
>