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From:   Oleksandr Mazur <oleksandr.mazur@plvision.eu>
To:     Andrew Lunn <andrew@lunn.ch>
CC:     "jiri@nvidia.com" <jiri@nvidia.com>,
        "davem@davemloft.net" <davem@davemloft.net>,
        "kuba@kernel.org" <kuba@kernel.org>,
        Vadym Kochan <vkochan@marvell.com>,
        Taras Chornyi <tchornyi@marvell.com>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Taras Chornyi <taras.chornyi@plvision.eu>,
        Vadym Kochan <vadym.kochan@plvision.eu>,
        Serhiy Pshyk <serhiy.pshyk@plvision.eu>,
        Volodymyr Mytnyk <volodymyr.mytnyk@plvision.eu>
Subject: Re: [PATCH net-next 10/11] net: marvell: prestera: add storm control
 (rate limiter) implementation
Thread-Topic: [PATCH net-next 10/11] net: marvell: prestera: add storm control
 (rate limiter) implementation
Thread-Index: AQHXXUJ5aWvncExU5U+sYOd/xLExb6sNMVAAgAGcSHI=
Date:   Fri, 11 Jun 2021 13:19:13 +0000
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References: <20210609151602.29004-1-oleksandr.mazur@plvision.eu>
 <20210609151602.29004-11-oleksandr.mazur@plvision.eu>,<YMIIcgKjIH5V+Exf@lunn.ch>
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>>  On Wed, Jun 09, 2021 at 06:16:00PM +0300, Oleksandr Mazur wrote:=0A=
> Storm control (BUM) provides a mechanism to limit rate of ingress=0A=
> > port traffic (matched by type). Devlink port parameter API is used:=0A=
> > driver registers a set of per-port parameters that can be accessed to b=
oth=0A=
> > get/set per-port per-type rate limit.=0A=
> > Add new FW command - RATE_LIMIT_MODE_SET.=0A=
=0A=
> Hi Oleksandr=0A=
=0A=
> Just expanding on the two comments you already received about this.=0A=
=0A=
> We often see people miss that switchdev is about. It is not about=0A=
> writing switch drivers. It is about writing network stack=0A=
> accelerators. You take a feature of the Linux network stack and you=0A=
> accelerate it by offloading it to the hardware. So look around the=0A=
> network stack and see how you configure it to perform rate limiting of=0A=
> broadcast traffic ingress. Once you have found a suitable mechanism,=0A=
> accelerate it via offloading.=0A=
=0A=
> If you find Linux has no way to perform a feature the hardware could=0A=
> accelerate, you first need to add a pure software version of that=0A=
> feature to the network stack, and then add acceleration support for=0A=
> it.=0A=
=0A=
=0A=
Hello Andrew, Ido, Nikolay,=0A=
I appreciate your time and comments provided over this patchset, though i h=
ave a few questions to ask, if you don't mind:=0A=
=0A=
1. Does it mean that in order to support storm control in switchdev driver =
i need to implement software storm control in bridge driver,=0A=
and then using the switchdev attributes (notifiers) mechanism offload the c=
onfiguration itself to the HW?=0A=
2. Is there any chance of keeping devlink solution untill the discussed (st=
orm control implemented in the bridge driver) mechanism will be ready/imple=
mented?=0A=
=0A=
Anyway, it relies on the port param API from devlink which is already prese=
nt in the kernel API.=