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From: Jeroen Hofstee <jhofstee@victronenergy.com>
To: Oliver Hartkopp <socketcan@hartkopp.net>,
	"linux-can@vger.kernel.org" <linux-can@vger.kernel.org>
Subject: Re: rx-dropped increases if the can module is not loaded (yet)
Date: Wed, 2 Dec 2020 16:47:50 +0100	[thread overview]
Message-ID: <dea3d0e6-9e75-671c-b318-830b080ce5d5@victronenergy.com> (raw)
In-Reply-To: <438db92e-692a-5fcf-db97-7ba3a51c97be@hartkopp.net>

Hello Oliver,

On 11/28/20 6:44 PM, Oliver Hartkopp wrote:
> On 27.11.20 17:09, Jeroen Hofstee wrote:
>
>> Since it took me a while to figure it out, it might be worthwhile to 
>> share.
>> If a CAN-bus network interface is first set to up and only later used,
>> the messages received in the meantime are counted by [1] as dropped.
>
> Interesting! But makes sense and is consistent: When the CAN frame is 
> not processed by the network layer is is just dropped in the rx path.
>
>> If the the can module is modprobed before the interface is upped, this
>> is no longer the case.
>>
>> Perhaps it saves someone some time.
>
> So far we have not documented these details for the existing netdev 
> statistics. Do you think this is needed when the behaviour, which 
> leads to rx-dropped, is common for other netdevs also?
>
>

Don't know... Perhaps we should simply wait and see how many
people show up wondering where the rx-dropped frames are
coming from?

Regards,

Jeroen


  reply	other threads:[~2020-12-02 15:48 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-27 16:09 rx-dropped increases if the can module is not loaded (yet) Jeroen Hofstee
2020-11-28 17:44 ` Oliver Hartkopp
2020-12-02 15:47   ` Jeroen Hofstee [this message]
2020-12-02 16:24     ` Oliver Hartkopp

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