From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [PATCH v3 08/10] doc: describe Rx bytes counter
 behavior for enic
Date: Thu, 8 Mar 2018 14:14:27 -0800
Message-ID: <20180308141427.08475f17@xeon-e3>
References: <20180306014634.28398-2-johndale@cisco.com>
 <20180308024702.25974-1-johndale@cisco.com>
 <20180308024702.25974-9-johndale@cisco.com>
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Cc: ferruh.yigit@intel.com, dev@dpdk.org, Hyong Youb Kim <hyonkim@cisco.com>
To: John Daley <johndale@cisco.com>
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On Wed,  7 Mar 2018 18:47:00 -0800
John Daley <johndale@cisco.com> wrote:

>      'catch-all' filters should be added last.
>  
> +- **Statistics**
> +
> +  - ``rx_good_bytes`` (ibytes) always includes VLAN header (4B) and CRC bytes (4B).
> +  - When the NIC drops a packet because the Rx queue has no free buffers,
> +    ``rx_good_bytes`` still increments by 4B if the packet is not VLAN tagged or
> +    VLAN stripping is disabled, or by 8B if the packet is VLAN tagged and stripping
> +    is enabled.

All drivers must provide consistent statistics!
That means do NOT include CRC in the rx byte counts.
Yes, several drivers in DPDK are already broken for this.

Otherwise there are cases like packets being forwarded from HW NIC to virtio and the counts
differ and customers think data is lots.