From: Jakub Kicinski <kuba@kernel.org>
To: Etienne Champetier <champetier.etienne@gmail.com>
Cc: netdev@vger.kernel.org
Subject: Re: Multicast packet reordering
Date: Fri, 2 Dec 2022 13:39:02 -0800 [thread overview]
Message-ID: <20221202133902.7888c0ce@kernel.org> (raw)
In-Reply-To: <CAOdf3goC0eXSqdpdcq_-4wegMTBmYdK_uQOKUpjX7azvTamWDA@mail.gmail.com>
On Fri, 2 Dec 2022 15:09:13 -0500 Etienne Champetier wrote:
> > Yes, there are per-cpu queues in various places to help scaling,
> > if you don't pin the sender to one CPU and it gets moved you can
> > understandably get reordering w/ UDP (both on lo and veth).
>
> Is enabling RPS a workaround that will continue to work in the long term,
> or it just fixes this reordering "by accident" ?
For lo and veth it should continue to work.
> And I guess pinning the sender to one CPU is also important when
> sending via a real NIC, not only moving packets internally ?
Yes, for UDP with real NICs you may want to try to pin a flow
to a particular NIC queue.. somehow. Not sure how much of a problem
this is in practice.
prev parent reply other threads:[~2022-12-02 21:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-02 4:45 Multicast packet reordering Etienne Champetier
2022-12-02 13:46 ` Andrew Lunn
2022-12-02 15:32 ` Etienne Champetier
2022-12-02 18:34 ` Jakub Kicinski
2022-12-02 20:09 ` Etienne Champetier
2022-12-02 21:39 ` Jakub Kicinski [this message]
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