From: Oleksij Rempel <o.rempel@pengutronix.de>
To: Devid Antonio Filoni <devid.filoni@egluetechnologies.com>,
Robin van der Gracht <robin@protonic.nl>,
kernel@pengutronix.de, linux-can@vger.kernel.org,
Oleksij Rempel <linux@rempel-privat.de>,
Oliver Hartkopp <socketcan@hartkopp.net>,
Marc Kleine-Budde <mkl@pengutronix.de>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Maxime Jayat <maxime.jayat@mobile-devices.fr>,
kbuild test robot <lkp@intel.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RESEND] can: j1939: do not wait 250ms if the same addr was already claimed
Date: Tue, 10 May 2022 06:26:09 +0200 [thread overview]
Message-ID: <20220510042609.GA10669@pengutronix.de> (raw)
In-Reply-To: <YnllpntZ8V5CD07v@x1.vandijck-laurijssen.be>
Hi,
On Mon, May 09, 2022 at 09:04:06PM +0200, Kurt Van Dijck wrote:
> On ma, 09 mei 2022 19:03:03 +0200, Devid Antonio Filoni wrote:
> > This is not explicitly stated in SAE J1939-21 and some tools used for
> > ISO-11783 certification do not expect this wait.
It will be interesting to know which certification tool do not expect it and
what explanation is used if it fails?
> IMHO, the current behaviour is not explicitely stated, but nor is the opposite.
> And if I'm not mistaken, this introduces a 250msec delay.
>
> 1. If you want to avoid the 250msec gap, you should avoid to contest the same address.
>
> 2. It's a balance between predictability and flexibility, but if you try to accomplish both,
> as your patch suggests, there is slight time-window until the current owner responds,
> in which it may be confusing which node has the address. It depends on how much history
> you have collected on the bus.
>
> I'm sure that this problem decreases with increasing processing power on the nodes,
> but bigger internal queues also increase this window.
>
> It would certainly help if you describe how the current implementation fails.
>
> Would decreasing the dead time to 50msec help in such case.
>
> Kind regards,
> Kurt
>
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next prev parent reply other threads:[~2022-05-10 4:29 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-09 17:03 [PATCH RESEND] can: j1939: do not wait 250ms if the same addr was already claimed Devid Antonio Filoni
2022-05-09 19:04 ` Kurt Van Dijck
2022-05-10 4:26 ` Oleksij Rempel [this message]
2022-05-10 11:00 ` Devid Antonio Filoni
2022-05-11 8:47 ` Oleksij Rempel
2022-05-11 9:06 ` David Jander
2022-05-11 12:55 ` Devid Antonio Filoni
2022-05-11 14:22 ` David Jander
2022-05-13 9:46 ` Devid Antonio Filoni
2022-11-17 14:08 ` Devid Antonio Filoni
2022-11-17 15:22 ` David Jander
2022-11-18 6:06 ` Oleksij Rempel
2022-11-18 10:25 ` Devid Antonio Filoni
2022-11-18 12:30 ` Oleksij Rempel
2022-11-18 12:41 ` Devid Antonio Filoni
2022-11-18 13:44 ` Oleksij Rempel
2022-11-18 15:12 ` Devid Antonio Filoni
2022-11-19 10:12 ` Oleksij Rempel
2022-11-20 0:11 ` Devid Antonio Filoni
2022-11-20 8:45 ` Oleksij Rempel
2022-11-20 19:18 ` Devid Antonio Filoni
2022-11-21 5:19 ` Oleksij Rempel
2022-11-23 20:39 ` Devid Antonio Filoni
2022-11-24 5:16 ` Oleksij Rempel
2022-11-25 17:04 ` [PATCH v2] can: j1939: do not wait 250 ms " Devid Antonio Filoni
2022-11-26 10:28 ` Oleksij Rempel
2023-02-07 13:50 ` Devid Antonio Filoni
2023-02-07 14:05 ` Marc Kleine-Budde
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