From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Grandegger Subject: Re: command ip -details -statistics link show wlan0 Date: Thu, 16 May 2013 09:02:03 +0200 Message-ID: <5194846B.1070307@grandegger.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from ngcobalt02.manitu.net ([217.11.48.102]:60511 "EHLO ngcobalt02.manitu.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755520Ab3EPHCH (ORCPT ); Thu, 16 May 2013 03:02:07 -0400 In-Reply-To: Sender: linux-can-owner@vger.kernel.org List-ID: To: Ernast Sevo Cc: linux-can@vger.kernel.org Hi Ernast, On 05/15/2013 08:58 PM, Ernast Sevo wrote: > Hello, > > I am quite new to socket can and I had a question about the output of > the command: ip -details -statistics link show can0. When I run the > above command I get the following output: > > re-started bus-errors arbit-lost error-warn error-pass bus-off > 0 0 0 0 0 0 > RX: bytes packets errors dropped overrun mcast > 3956387 948121 11 0 11 0 > TX: bytes packets errors dropped carrier collsns > 100 44 0 0 0 0 > > > I see that I received 11 errors packets (all of them being rx overrun > errors) and that no packets were dropped. Does the dropped field refer > to packets lost in userspace (i.e because they weren't being read fast > enough and the socket receive buffer overflowed) or does the dropped > packet field refer to dropped packets being dropped somewhere other > than userspace? They refer to packets dropped in the driver for some reason, maily because memory is short (ENOMEM). The overrun errors above are reported by the hardware due to messages arrived but there was no space to store it. Messages dropped because the socket buffer was full can be reported with the candump option "-d" as shown here: https://gitorious.org/linux-can/can-utils/blobs/master/candump.c#line549 Hope that helps. Wolfgang.