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Date:   Wed, 7 Jun 2023 13:30:01 +0300
From:   Vladimir Oltean <vladimir.oltean@nxp.com>
To:     Jamal Hadi Salim <jhs@mojatatu.com>
Cc:     netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        Jiri Pirko <jiri@resnulli.us>,
        Vinicius Costa Gomes <vinicius.gomes@intel.com>,
        linux-kernel@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
        Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>,
        Peilin Ye <yepeilin.cs@gmail.com>,
        Pedro Tammela <pctammela@mojatatu.com>
Subject: Re: [PATCH RESEND net-next 0/5] Improve the taprio qdisc's
 relationship with its children
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On Wed, Jun 07, 2023 at 01:09:01PM +0300, Vladimir Oltean wrote:
> That being said, a non-offloaded cbs/htb will not work with an offloaded
> taprio root anymore after commit 13511704f8d7 ("net: taprio offload:
> enforce qdisc to netdev queue mapping"), and IMO what should be done
> there is to reject somehow those child Qdiscs which also can't be
> offloaded when the root is offloaded.
> 
> Offloading a taprio qdisc (potentially with offloaded cbs children) also
> affects the autonomous forwarding data path in case of an Ethernet switch.
> So it's not just about dev_queue_xmits() from Linux.

Ah, no, I said something stupid. Non-offloaded child Qdisc should still
work with offloaded root (shaping done in software, scheduling in hardware).
I was thinking about the autonomous forwarding case in the back of my
mind, that's still problematic because the shaping wouldn't affect the
packets that Linux didn't originate.