netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Marek Behun <marek.behun@nic.cz>
To: Vladimir Oltean <olteanv@gmail.com>
Cc: "DENG Qingfang" <dqfext@gmail.com>,
	"Ansuel Smith" <ansuelsmth@gmail.com>,
	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>,
	"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: Tue, 13 Apr 2021 00:47:06 +0200	[thread overview]
Message-ID: <20210413004706.6413d615@thinkpad> (raw)
In-Reply-To: <20210412221721.3gszur3hbrkhe76m@skbuf>

On Tue, 13 Apr 2021 01:17:21 +0300
Vladimir Oltean <olteanv@gmail.com> wrote:

> On Tue, Apr 13, 2021 at 12:04:57AM +0200, Marek Behun wrote:
> > On Mon, 12 Apr 2021 19:32:11 +0300
> > Vladimir Oltean <olteanv@gmail.com> wrote:
> >  
> > > On Mon, Apr 12, 2021 at 11:00:45PM +0800, DENG Qingfang wrote:  
> > > > On Sun, Apr 11, 2021 at 09:50:17PM +0300, Vladimir Oltean wrote:  
> > > > >
> > > > > So I'd be tempted to say 'tough luck' if all your ports are not up, and
> > > > > the ones that are are assigned statically to the same CPU port. It's a
> > > > > compromise between flexibility and simplicity, and I would go for
> > > > > simplicity here. That's the most you can achieve with static assignment,
> > > > > just put the CPU ports in a LAG if you want better dynamic load balancing
> > > > > (for details read on below).
> > > > >  
> > > >
> > > > Many switches such as mv88e6xxx only support MAC DA/SA load balancing,
> > > > which make it not ideal in router application (Router WAN <--> ISP BRAS
> > > > traffic will always have the same DA/SA and thus use only one port).  
> > >
> > > Is this supposed to make a difference? Choose a better switch vendor!  
> >
> > :-) Are you saying that we shall abandon trying to make the DSA
> > subsystem work with better performace for our routers, in order to
> > punish ourselves for our bad decision to use Marvell switches?  
> 
> No, not at all, I just don't understand what is the point you and
> Qingfang are trying to make.

I am not trying to make a point for this patch series. I did not touch
it since the last time I sent it. Ansuel just took over this series and
I am just contributing my thoughts to the RFC :)

I agree with you that this patch series still needs a lot of work.

> LAG is useful in general for load balancing.
> With the particular case of point-to-point links with Marvell Linkstreet,
> not so much. Okay. With a different workload, maybe it is useful with
> Marvell Linkstreet too. Again okay. Same for static assignment,
> sometimes it is what is needed and sometimes it just isn't.
> It was proposed that you write up a user space program that picks the
> CPU port assignment based on your favorite metric and just tells DSA to
> reconfigure itself, either using a custom fancy static assignment based
> on traffic rate (read MIB counters every minute) or simply based on LAG.
> All the data laid out so far would indicate that this would give you the
> flexibility you need, however you didn't leave any comment on that,
> either acknowledging or explaining why it wouldn't be what you want.

Yes, you are right. A custom userspace utility for assigning CPU ports
would be better here than adding lots of complication into the kernel
abstraction.

  reply	other threads:[~2021-04-12 22:47 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 ` [PATCH RFC net-next 0/3] Multi-CPU DSA support Marek Behun
2021-04-11 18:08   ` 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 [this message]
  -- 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

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=20210413004706.6413d615@thinkpad \
    --to=marek.behun@nic.cz \
    --cc=andrew@lunn.ch \
    --cc=andriin@fb.com \
    --cc=ansuelsmth@gmail.com \
    --cc=ap420073@gmail.com \
    --cc=ast@kernel.org \
    --cc=bjorn@kernel.org \
    --cc=chenweilong@huawei.com \
    --cc=cong.wang@bytedance.com \
    --cc=daniel@iogearbox.net \
    --cc=davem@davemloft.net \
    --cc=dqfext@gmail.com \
    --cc=edumazet@google.com \
    --cc=f.fainelli@gmail.com \
    --cc=kuba@kernel.org \
    --cc=laniel_francis@privacyrequired.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=olteanv@gmail.com \
    --cc=roopa@cumulusnetworks.com \
    --cc=vivien.didelot@gmail.com \
    --cc=weiwan@google.com \
    --cc=zhangkaiheb@126.com \
    --cc=zhudi21@huawei.com \
    /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).