From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Hartkopp Subject: Re: C_CAN: can frame drops Date: Thu, 24 Jul 2014 20:09:43 +0200 Message-ID: <53D14BE7.6030007@hartkopp.net> References: ,<53CFDD24.3070004@hartkopp.net>, Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mo4-p00-ob.smtp.rzone.de ([81.169.146.217]:23901 "EHLO mo4-p00-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932742AbaGXSJu (ORCPT ); Thu, 24 Jul 2014 14:09:50 -0400 In-Reply-To: Sender: linux-can-owner@vger.kernel.org List-ID: To: Ssagarr Patil Cc: "linux-can@vger.kernel.org" Hi Sagar, unfortunately I'm not really a C_CAN expert. I know from a Beaglebone Black which run's at 99% busload without any issues on the two integrated D_CAN controllers. Do you have these problems with a stock 2.6.37.x on your hardware too? Can you send the dmesg output of the c_can related content? Regards, Oliver On 24.07.2014 09:40, Ssagarr Patil wrote: >> Hi Oliver, >> >> Thanks for your response :-) >> >>> >>> generally dropping CAN frames on driver level is a complete different problem >>> in opposite to dropping CAN frames on socket receive level. >>> >> Agreed. >> >>> A drop on the socket layer usually occurs, when the application does not get >>> enough CPU time to read and process the CAN frames. But drops on CAN driver >>> layer lead to a possible resource problem on your system. >>> >> For the application layer I have used chrt so that it gets higher priority. >> >>> Can you tell a bit more about your platform (hardware, CPU, cpu clock, RAM) >>> and Linux Kernel version? >>> >> The Linux version is 2.6.37 where as I have patched this kernel to use the v3.15 >> C_CAN driver(which uses D_CAN) to use. >> >> Hardware is DM8148 EVM, ARM clock is @1000Mhz, DDR @533Mhz, > > BTW I also tried it on AM335x with the v3.16-rc5 which supports D_CAN > the problem is the same. > > Thanks, > --Sagar > >> >> Regards, >> --Sagar >> >>> Regards, >>> Oliver >>> >>> >>> On 23.07.2014 16:48, Ssagarr Patil wrote: >>>> Hi, >>>> >>>> I am using the c_can driver for latest kernel and using the latest canutils to dump to a file. >>>> My can bus is set at a rate of 1Mb (receiving 7000fps bus load of 80%). >>>> >>>> When I use the candump tool to dump can frames I get following message, >>>> >>>> 'DROPCOUNT: dropped 2223 CAN frames on 'any' socket (total drops 1629092)' >>>> >>>> SO to solve this problem if I use the -r option of candump and tried >>>> candump any -d -e -r 999999999 -l >>>> >>>> If I do this the can frames are dropped in the driver ie I see >>>> this c_can_handle_lost_msg_obj() function being called frequently in which can frame >>>> is overwritten. >>>> >>>> How to solve this issue any pointers would be helpful. >>>> >>>> Thanks, >>>> --Sagar >>>> -- >>>> To unsubscribe from this list: send the line "unsubscribe linux-can" in >>>> the body of a message to majordomo@vger.kernel.org >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-can" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > >