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From: Marek Behun <marek.behun@nic.cz>
To: Ansuel Smith <ansuelsmth@gmail.com>
Cc: netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"Andrew Lunn" <andrew@lunn.ch>,
	"Vivien Didelot" <vivien.didelot@gmail.com>,
	"Florian Fainelli" <f.fainelli@gmail.com>,
	"Vladimir Oltean" <olteanv@gmail.com>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Andrii Nakryiko" <andriin@fb.com>,
	"Eric Dumazet" <edumazet@google.com>,
	"Wei Wang" <weiwan@google.com>,
	"Cong Wang" <cong.wang@bytedance.com>,
	"Taehee Yoo" <ap420073@gmail.com>,
	"Björn Töpel" <bjorn@kernel.org>,
	"zhang kai" <zhangkaiheb@126.com>,
	"Weilong Chen" <chenweilong@huawei.com>,
	"Roopa Prabhu" <roopa@cumulusnetworks.com>,
	"Di Zhu" <zhudi21@huawei.com>,
	"Francis Laniel" <laniel_francis@privacyrequired.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC net-next 0/3] Multi-CPU DSA support
Date: Sun, 11 Apr 2021 20:01:35 +0200	[thread overview]
Message-ID: <20210411200135.35fb5985@thinkpad> (raw)
In-Reply-To: <20210410133454.4768-1-ansuelsmth@gmail.com>

On Sat, 10 Apr 2021 15:34:46 +0200
Ansuel Smith <ansuelsmth@gmail.com> wrote:

> Hi,
> this is a respin of the Marek series in hope that this time we can
> finally make some progress with dsa supporting multi-cpu port.
> 
> This implementation is similar to the Marek series but with some tweaks.
> This adds support for multiple-cpu port but leave the driver the
> decision of the type of logic to use about assigning a CPU port to the
> various port. The driver can also provide no preference and the CPU port
> is decided using a round-robin way.

In the last couple of months I have been giving some thought to this
problem, and came up with one important thing: if there are multiple
upstream ports, it would make a lot of sense to dynamically reallocate
them to each user port, based on which user port is actually used, and
at what speed.

For example on Turris Omnia we have 2 CPU ports and 5 user ports. All
ports support at most 1 Gbps. Round-robin would assign:
  CPU port 0 - Port 0
  CPU port 1 - Port 1
  CPU port 0 - Port 2
  CPU port 1 - Port 3
  CPU port 0 - Port 4

Now suppose that the user plugs ethernet cables only into ports 0 and 2,
with 1, 3 and 4 free:
  CPU port 0 - Port 0 (plugged)
  CPU port 1 - Port 1 (free)
  CPU port 0 - Port 2 (plugged)
  CPU port 1 - Port 3 (free)
  CPU port 0 - Port 4 (free)

We end up in a situation where ports 0 and 2 share 1 Gbps bandwidth to
CPU, and the second CPU port is not used at all.

A mechanism for automatic reassignment of CPU ports would be ideal here.

What do you guys think?

Marek

  parent reply	other threads:[~2021-04-11 18:01 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-10 13:34 [PATCH RFC net-next 0/3] Multi-CPU DSA support Ansuel Smith
2021-04-10 13:34 ` [PATCH RFC net-next 1/3] net: dsa: allow for multiple CPU ports Ansuel Smith
2021-04-12  3:35   ` DENG Qingfang
2021-04-12  4:41     ` Ansuel Smith
2021-04-12 15:30       ` DENG Qingfang
2021-04-12 16:17         ` Frank Wunderlich
2021-04-10 13:34 ` [PATCH RFC net-next 2/3] net: add ndo for setting the iflink property Ansuel Smith
2021-04-10 13:34 ` [PATCH RFC net-next 3/3] net: dsa: implement ndo_set_netlink for chaning port's CPU port Ansuel Smith
2021-04-10 13:34 ` [PATCH RFC iproute2-next] iplink: allow to change iplink value Ansuel Smith
2021-04-11 17:04   ` Stephen Hemminger
2021-04-11 17:09     ` Vladimir Oltean
2021-04-11 18:01 ` Marek Behun [this message]
2021-04-11 18:08   ` [PATCH RFC net-next 0/3] Multi-CPU DSA support Ansuel Smith
2021-04-11 18:39   ` Andrew Lunn
2021-04-12  2:07     ` Florian Fainelli
2021-04-12  4:53     ` Ansuel Smith
2021-04-11 18:50   ` Vladimir Oltean
2021-04-11 23:53     ` Vladimir Oltean
2021-04-12  2:10       ` Florian Fainelli
2021-04-12  5:04     ` Ansuel Smith
2021-04-12 12:46     ` Tobias Waldekranz
2021-04-12 14:35       ` Vladimir Oltean
2021-04-12 21:06         ` Tobias Waldekranz
2021-04-12 19:30       ` Marek Behun
2021-04-12 21:22         ` Tobias Waldekranz
2021-04-12 21:34           ` Vladimir Oltean
2021-04-12 21:49             ` Tobias Waldekranz
2021-04-12 21:56               ` Marek Behun
2021-04-12 22:06               ` Vladimir Oltean
2021-04-12 22:26                 ` Tobias Waldekranz
2021-04-12 22:48                   ` Vladimir Oltean
2021-04-12 23:04                     ` Marek Behun
2021-04-12 21:50           ` Marek Behun
2021-04-12 22:05             ` Tobias Waldekranz
2021-04-12 22:55               ` Marek Behun
2021-04-12 23:09                 ` Tobias Waldekranz
2021-04-12 23:13                   ` Tobias Waldekranz
2021-04-12 23:54                     ` Marek Behun
2021-04-13  0:27                       ` Marek Behun
2021-04-13  0:31                         ` Marek Behun
2021-04-13 14:46                         ` Tobias Waldekranz
2021-04-13 15:14                           ` Marek Behun
2021-04-13 18:16                             ` Tobias Waldekranz
2021-04-14 15:14                               ` Marek Behun
2021-04-14 18:39                                 ` Tobias Waldekranz
2021-04-14 23:39                                   ` Vladimir Oltean
2021-04-15  9:20                                     ` Tobias Waldekranz
2021-04-13 14:40                       ` Tobias Waldekranz
2021-04-12 15:00     ` DENG Qingfang
2021-04-12 16:32       ` Vladimir Oltean
2021-04-12 22:04         ` Marek Behun
2021-04-12 22:17           ` Vladimir Oltean
2021-04-12 22:47             ` Marek Behun
  -- strict thread matches above, loose matches on Subject: below --
2019-08-24  2:42 Marek Behún
2019-08-24 15:24 ` Andrew Lunn
2019-08-24 17:45   ` Marek Behun
2019-08-24 17:54     ` Andrew Lunn
2019-08-25  4:19   ` Marek Behun
2019-08-24 15:40 ` Vladimir Oltean
2019-08-24 15:44   ` Vladimir Oltean
2019-08-24 17:55     ` Marek Behun
2019-08-24 15:56   ` Andrew Lunn
2019-08-24 17:58     ` Marek Behun
2019-08-24 20:04 ` Florian Fainelli
2019-08-24 21:01   ` Marek Behun
2019-08-25  4:08     ` Marek Behun
2019-08-25  7:13   ` Marek Behun
2019-08-25 15:00     ` Florian Fainelli

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