Bug 2187733 - vhost interface packet size reporting
Summary: vhost interface packet size reporting
Keywords:
Status: ASSIGNED
Alias: None
Product: Red Hat Enterprise Linux Fast Datapath
Classification: Red Hat
Component: openvswitch3.1
Version: FDP 23.B
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
: ---
Assignee: Maxime Coquelin
QA Contact: Jiying Qiu
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2023-04-18 14:46 UTC by Kevin Traynor
Modified: 2023-07-31 16:55 UTC (History)
5 users (show)

Fixed In Version:
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System ID Private Priority Status Summary Last Updated
Red Hat Issue Tracker FD-2824 0 None None None 2023-04-18 14:47:28 UTC

Description Kevin Traynor 2023-04-18 14:46:06 UTC
Description of problem:
As per https://www.rfc-editor.org/rfc/rfc2819.html stats for packet size are reported "including FCS".

However in DPDK vhost the packet size is being reported without an FCS which leads to a 4 byte offset in stat value. This means that packets near a boundary may be counted in the wrong packet size bucket.

It also means that for a PVP test using 64 byte packets from the traffic gen, the packets are being reported from vhost as 60 byte packets which increments the undersize pkts counters that is then reported in OVS stats.

This issue reported in https://bugzilla.redhat.com/show_bug.cgi?id=2175079#c10

Version-Release number of selected component (if applicable):
DPDK 22.11 (OVS 3.1)

Steps to Reproduce:
1. Setup PVP test with 64 byte packets
2. Check OVS vhost stats for undersize packets


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