From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?Q?Andr=c3=a9_Hartmann?= Subject: Re: Need help in interpreting ip status output Date: Sat, 21 Mar 2020 16:19:39 +0100 Message-ID: <75a1a6b5-141e-e741-f6c2-bab5e9e4e541@gmx.de> References: <86b34b1b-7bda-e481-2087-1be8e64d2fed@hartkopp.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: Received: from mout.gmx.net ([212.227.17.22]:45859 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727015AbgCUPTk (ORCPT ); Sat, 21 Mar 2020 11:19:40 -0400 In-Reply-To: <86b34b1b-7bda-e481-2087-1be8e64d2fed@hartkopp.net> Content-Language: en-GB Sender: linux-can-owner@vger.kernel.org List-ID: To: Oliver Hartkopp , "linux-can@vger.kernel.org" Cc: Alex Blasche Hi Oliver, thanks for your answer. I hope you are well. > Hi Andr=C3=A9, > > I have an idea ;-) > > On 12/03/2020 18.43, Andr=C3=A9 Hartmann wrote: > >>> can someone help me interpreting the following ip output: >>> >>> ip -s link show can1 >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 3: can1: mtu 1= 6 qdisc pfifo_fast state >>> UNKNOWN mode DEFAULT group default qlen 100 >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 link/can >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 RX: bytes=C2=A0= packets=C2=A0 errors=C2=A0 dropped overrun mcast >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 9987413=C2=A0 1=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0 74=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 1=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0 0 >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 TX: bytes=C2=A0= packets=C2=A0 errors=C2=A0 dropped carrier collsns >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0 0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0 0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0 >>> >>> I'm especially interested in the meaning of the >>> >>> * 1 errors >>> * 74 dropped >>> * 1 overrun > > E.g. if you look into > linux/drivers/net/can/sja1000/sja1000.c > you can see that an overrun error also triggers the error counter to > increase - that's why both are set to 1. > > The reason for the overrun error is a notification from the CAN > controller itself. It tells us that the received CAN frame has not been > read from the controller until the next CAN frame arrived. Ok, that's what I thought too, thanks for the confirmation. > The dropped counter usually indicates that the CAN driver did not get a > skbuff data structure (e.g. out of memory condition). > > This is NOT good. What CAN hardware/setup are you using? Actually it's not my system. The report is from a customer doing a full load test on an iMX8: https://bugreports.qt.io/browse/QTBUG-82610 I guess the customer should try a more recent Kernel than 4.14 first? Thanks, and best regards, Andr=C3=A9 > > Regards, > Oliver