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 10:34:29 -0800 [thread overview]
Message-ID: <20221202103429.1887d586@kernel.org> (raw)
In-Reply-To: <e0f9fb60-b09c-30ad-0670-aa77cc3b2e12@gmail.com>
On Thu, 1 Dec 2022 23:45:53 -0500 Etienne Champetier wrote:
> Using RPS fixes the issue, but to make it short:
> - Is it expect to have multicast packet reordering when just tuning buffer sizes ?
> - Does it make sense to use RPS to fix this issue / anything else / better ?
> - In the case of 2 containers talking using veth + bridge, is it better to keep 1 queue
> and set rps_cpus to all cpus, or some more complex tuning like 1 queue per cpu + rps on 1 cpu only ?
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).
As Andrew said that's considered acceptable.
Unfortunately it's one of those cases where we need to relax
the requirements / stray from the ideal world if we want parallel
processing to not suck..
next prev parent reply other threads:[~2022-12-02 18:34 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 [this message]
2022-12-02 20:09 ` Etienne Champetier
2022-12-02 21:39 ` Jakub Kicinski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20221202103429.1887d586@kernel.org \
--to=kuba@kernel.org \
--cc=champetier.etienne@gmail.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).