From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 3E43545538; Mon, 1 Jul 2024 18:45:08 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 167114014F; Mon, 1 Jul 2024 18:45:08 +0200 (CEST) Received: from inbox.dpdk.org (inbox.dpdk.org [95.142.172.178]) by mails.dpdk.org (Postfix) with ESMTP id 6F499400EF for ; Mon, 1 Jul 2024 18:45:07 +0200 (CEST) Received: by inbox.dpdk.org (Postfix, from userid 33) id 608FE4553B; Mon, 1 Jul 2024 18:45:07 +0200 (CEST) From: bugzilla@dpdk.org To: dev@dpdk.org Subject: [DPDK/ethdev Bug 1476] Frame Overhead Inconsistencies Within Drivers Date: Mon, 01 Jul 2024 16:45:07 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: DPDK X-Bugzilla-Component: ethdev X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: npratte@iol.unh.edu X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: Normal X-Bugzilla-Assigned-To: dev@dpdk.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter target_milestone Message-ID: Content-Type: multipart/alternative; boundary=17198523070.ddEB22.1455053 Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://bugs.dpdk.org/ Auto-Submitted: auto-generated X-Auto-Response-Suppress: All MIME-Version: 1.0 X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org --17198523070.ddEB22.1455053 Date: Mon, 1 Jul 2024 18:45:07 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://bugs.dpdk.org/ Auto-Submitted: auto-generated X-Auto-Response-Suppress: All https://bugs.dpdk.org/show_bug.cgi?id=3D1476 Bug ID: 1476 Summary: Frame Overhead Inconsistencies Within Drivers Product: DPDK Version: unspecified Hardware: All OS: All Status: UNCONFIRMED Severity: normal Priority: Normal Component: ethdev Assignee: dev@dpdk.org Reporter: npratte@iol.unh.edu Target Milestone: --- There are inconsistencies within DPDK network drivers regarding how it calculates Ethernet overhead. These calculations have meaningful impacts towards how we write test suites to assess the ethdev API, namely MTUs.=20 Network drivers base their implementations of rte_ethdev's set_mtu() on arbitrary Ethernet overhead constants specific to the individual network driver. For example, the file bnxt_ethdev.c assumes an Ethernet overhead of= the standard 14 byte Ether header, CRC, and space for QinQ; i40e makes the same assumptions. Mellanox, however, assumes only for a 14 byte Ether header plus CRC, so the overall Ether overhead is different between NICs. DPDK drops or forwards packets based on the total frame size, not the L3 packet/MTU size.= So, the result is that we can set the MTU the same way for different devices and see different behavior. If we want to, for example, test MTUs without concern for individual behavi= or, then we need to discuss what the proper amount of assumed overhead is befor= e we can consider it a bug. --=20 You are receiving this mail because: You are the assignee for the bug.= --17198523070.ddEB22.1455053 Date: Mon, 1 Jul 2024 18:45:07 +0200 MIME-Version: 1.0 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://bugs.dpdk.org/ Auto-Submitted: auto-generated X-Auto-Response-Suppress: All
Bug ID 1476
Summary Frame Overhead Inconsistencies Within Drivers
Product DPDK
Version unspecified
Hardware All
OS All
Status UNCONFIRMED
Severity normal
Priority Normal
Component ethdev
Assignee dev@dpdk.org
Reporter npratte@iol.unh.edu
Target Milestone --- 

There are inconsistencies within D=
PDK network drivers regarding how it
calculates Ethernet overhead. These calculations have meaningful impacts
towards how we write test suites to assess the ethdev API, namely MTUs.=20

Network drivers base their implementations of rte_ethdev's set_mtu() on
arbitrary Ethernet overhead constants specific to the individual network
driver. For example, the file bnxt_ethdev.c assumes an Ethernet overhead of=
 the
standard 14 byte Ether header, CRC, and space for QinQ; i40e makes the same
assumptions. Mellanox, however, assumes only for a 14 byte Ether header plus
CRC, so the overall Ether overhead is different between NICs. DPDK drops or
forwards packets based on the total frame size, not the L3 packet/MTU size.=
 So,
the result is that we can set the MTU the same way for different devices and
see different behavior.

If we want to, for example, test MTUs without concern for individual behavi=
or,
then we need to discuss what the proper amount of assumed overhead is befor=
e we
can consider it a bug.

You are receiving this mail because:
  • You are the assignee for the bug.
=20=20=20=20=20=20=20=20=20=20
= --17198523070.ddEB22.1455053--