Date: Tue, 29 Aug 2017 14:50:04 +0200
From: Andrew Lunn <andrew@lunn.ch>
To: 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
Message-ID: <20170829125004.GB22093@lunn.ch>
References: <20170828191748.19492-1-vivien.didelot@savoirfairelinux.com>
 <20170828195332.GB1950@nanopsycho.orion>
 <20170828200834.GA1870@lunn.ch>
 <20170829062523.GA1977@nanopsycho.orion>
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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.

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://github.com/lunn/linux.git v4.11-rc4-net-next-dpipe

	 Andrew