netdev - Re: [Intel-wired-lan] [PATCH iwl-next v2] igc: Change Tx mode for MQPRIO offloading

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1e8e6855-0c87-4007-aadd-bdcad51f97cf@molgen.mpg.de>
Date: Mon, 24 Feb 2025 22:59:31 +0100
From: Paul Menzel <pmenzel@...gen.mpg.de>
To: Kurt Kanzenbach <kurt@...utronix.de>
Cc: Tony Nguyen <anthony.l.nguyen@...el.com>,
 Przemek Kitszel <przemyslaw.kitszel@...el.com>,
 Faizal Rahim <faizal.abdul.rahim@...ux.intel.com>,
 Andrew Lunn <andrew+netdev@...n.ch>, "David S. Miller"
 <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
 Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
 intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org
Subject: Re: [Intel-wired-lan] [PATCH iwl-next v2] igc: Change Tx mode for
 MQPRIO offloading

Dear Kurt,

Thank you for the patch.

Am 24.02.25 um 11:05 schrieb Kurt Kanzenbach:
> The current MQPRIO offload implementation uses the legacy TSN Tx mode. In
> this mode the hardware uses four packet buffers and considers queue
> priorities.

If I didn’t miss anything, later on you do not specify how many buffers 
are used after changing the Tx mode.

> In order to harmonize the TAPRIO implementation with MQPRIO, switch to the
> regular TSN Tx mode. In addition to the legacy mode, transmission is always
> coupled to Qbv. The driver already has mechanisms to use a dummy schedule
> of 1 second with all gates open for ETF. Simply use this for MQPRIO too.
> 
> This reduces code and makes it easier to add support for frame preemption
> later.
> 
> While at it limit the netdev_tc calls to MQPRIO only.
> 
> Tested on i225 with real time application using high priority queue, iperf3
> using low priority queue and network TAP device.
> 
> Signed-off-by: Kurt Kanzenbach <kurt@...utronix.de>
> ---
> Changes in v2:
> - Add comma to commit message (Faizal)
> - Simplify if condition (Faizal)
> - Link to v1: https://lore.kernel.org/r/20250217-igc_mqprio_tx_mode-v1-1-3a402fe1f326@linutronix.de
> ---
>   drivers/net/ethernet/intel/igc/igc.h      |  4 +---
>   drivers/net/ethernet/intel/igc/igc_main.c | 18 +++++++++++++-
>   drivers/net/ethernet/intel/igc/igc_tsn.c  | 40 ++-----------------------------
>   3 files changed, 20 insertions(+), 42 deletions(-)

[…]

Kind regards,

Paul