Re: [PATCH net-next v2 00/10] net: dsa: add generic debugfs interface

From: Arkadi Sharshevsky <arkadis@mellanox.com>
To: Andrew Lunn <andrew@lunn.ch>, Jiri Pirko <jiri@resnulli.us>
Cc: Vivien Didelot <vivien.didelot@savoirfairelinux.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel@savoirfairelinux.com,
	"David S. Miller" <davem@davemloft.net>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Egil Hjelmeland <privat@egil-hjelmeland.no>,
	John Crispin <john@phrozen.org>,
	Woojung Huh <Woojung.Huh@microchip.com>,
	Sean Wang <sean.wang@mediatek.com>,
	Nikita Yushchenko <nikita.yoush@cogentembedded.com>,
	Chris Healy <cphealy@gmail.com>,
	mlxsw@mellanox.com
Subject: Re: [PATCH net-next v2 00/10] net: dsa: add generic debugfs interface
Date: Tue, 29 Aug 2017 22:05:11 +0300	[thread overview]
Message-ID: <8e6fa7ea-fb7b-3026-b9c0-417ef2efae27@mellanox.com> (raw)
In-Reply-To: <20170829125004.GB22093@lunn.ch>

On 08/29/2017 03:50 PM, Andrew Lunn wrote:
> On Tue, Aug 29, 2017 at 08:25:23AM +0200, Jiri Pirko wrote:
>> Mon, Aug 28, 2017 at 10:08:34PM CEST, andrew@lunn.ch wrote:
>>>> I see this overlaps a lot with DPIPE. Why won't you use that to expose
>>>> your hw state?
>>>
>>> We took a look at dpipe and i talked to you about using it for this
>>> sort of thing at netconf/netdev. But dpipe has issues displaying the
>>> sort of information we have. I never figured out how to do two
>>> dimensional tables. The output of the dpipe command is pretty
>>> unreadable. A lot of the information being dumped here is not about
>>> the data pipe, etc.
>>
>> So improve it. No problem. Also, we extend it to support what you neede.
> 
> Will i did try to do this back in March. And i failed.
> 
> Lets start with stats. Vivien gives an example on the cover letter:
> 
>     # pr -mt switch0/port{5,6}/stats
>     in_good_octets      : 0             in_good_octets      : 13824
>     in_bad_octets       : 0             in_bad_octets       : 0
>     in_unicast          : 0             in_unicast          : 0
>     in_broadcasts       : 0             in_broadcasts       : 216
>     in_multicasts       : 0             in_multicasts       : 0
>     in_pause            : 0             in_pause            : 0
>     in_undersize        : 0             in_undersize        : 0
> 
> This is what i tried to implement using dpipe. It is a simple two
> dimensional table. First column is a string, second a u64. In debugfs
> we have such a table per port. That fits with the hierarchy that each
> port is a directory in debugfs. But it could also be implemented as
> one table with N+1 columns, for N switch ports.
>

Hi Andrew,

This looks to me like basic L2 statistics that are obtained via
ethtool, I remember you had this problem with the DSA and CPU port.
Is this still the case?

I remembered we wanted to use dpipe for the DSA routing table
and IP priority table.

I think both those processes really look like match/action table
, thus they can be modeled successfully by dpipe.

> How about you, or one of your team, implement that. It should be able
> to use the dsa_loop driver, which is a simple dummy switch. But it
> does have statistics counters for all ports. Florian or I can help you
> get it running if needed.
> 
> This branch contains some of the basic plumbing code from my previous
> attempt:
> 
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Flunn%2Flinux.git&data=02%7C01%7Carkadis%40mellanox.com%7Cb3cac139af204f79259c08d4eedc8410%7Ca652971c7d2e4d9ba6a4d149256f461b%7C0%7C0%7C636396078291326351&sdata=K5D3TAb2spckuF5k88oOaVt0dmtHj0AwE8bEEGPPdGI%3D&reserved=0 v4.11-rc4-net-next-dpipe
> 
> 	 Andrew
> 