From: Ferenc Fejes <fejes@inf.elte.hu>
To: John Ousterhout <ouster@cs.stanford.edu>, netdev@vger.kernel.org
Subject: Re: Bypass qdiscs?
Date: Sat, 04 Nov 2023 10:24:10 +0100 [thread overview]
Message-ID: <56f87c0304f8e4398d314992d1d872a7772eec9a.camel@inf.elte.hu> (raw)
In-Reply-To: <CAGXJAmy-0_GV7pR5_3NNArWZumunRijHeSJnY=VEf8RjmegZZw@mail.gmail.com>
Hi!
On Fri, 2023-11-03 at 16:55 -0700, John Ousterhout wrote:
> Is there a way to mark an skb (or its socket) before invoking
> ip_queue_xmit/ip6_xmit so that the packet will bypass the qdiscs and
> be transmitted immediately? Is doing such a thing considered bad
> practice?
I'm not aware if we have such thing aside from the AF_PACKET's flag
PACKET_QDISC_BYPASS [1,2]. I think the function packet_xmit [3]
utilizing that flag can be reused for your needs as well.
>
> (Homa has its own packet scheduling mechanism so the qdiscs are just
> getting in the way and adding delays)
>
> -John-
Best,
Ferenc
[1] https://man7.org/linux/man-pages/man7/packet.7.html
[2]
https://elixir.bootlin.com/linux/v6.6/source/net/packet/af_packet.c#L4026
[3]
https://elixir.bootlin.com/linux/v6.6/source/net/packet/af_packet.c#L273
next prev parent reply other threads:[~2023-11-04 9:24 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-03 23:55 Bypass qdiscs? John Ousterhout
2023-11-04 9:24 ` Ferenc Fejes [this message]
2023-11-04 15:08 ` Andrew Lunn
2023-11-05 2:47 ` John Ousterhout
2023-11-06 3:23 ` Stephen Hemminger
2023-11-06 4:27 ` David Ahern
2023-11-06 16:12 ` Jamal Hadi Salim
2023-11-06 16:17 ` Jamal Hadi Salim
2023-11-06 16:51 ` David Ahern
2023-11-08 16:50 ` John Ousterhout
2023-11-08 17:17 ` David Ahern
2023-11-09 17:50 ` David Laight
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