From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 31 Jan 2001 04:20:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 31 Jan 2001 04:19:55 -0500 Received: from pop.gmx.net ([194.221.183.20]:60554 "HELO mail.gmx.net") by vger.kernel.org with SMTP id ; Wed, 31 Jan 2001 04:19:44 -0500 Message-ID: <3A77D89C.20E0AC72@gmx.de> Date: Wed, 31 Jan 2001 10:19:25 +0100 From: Martin Rauh X-Mailer: Mozilla 4.6 [de] (WinNT; U) X-Accept-Language: de MIME-Version: 1.0 To: Andi Kleen CC: linux-kernel@vger.kernel.org Subject: Re: Packet loss in IP/UDP Stack? In-Reply-To: <3A71BB68.21B998AB@gmx.de> <20010126190856.A19098@gruyere.muc.suse.de> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org The UDP packet loss went away by setting the rmem_max and rmem_default in /proc/sys/net/core on the receiving linux box to about 80 percent of the size of the transfered file (~50MB). Many thanks for the fast help! greetings, Martin Rauh Andi Kleen wrote: > On Fri, Jan 26, 2001 at 07:01:12PM +0100, Martin Rauh wrote: > > Hi folks, > > > > It seems that we are loosing packets in the UDP stack. > > Somebody might think that this is not astonishing, but > > the packets are not lost at the network layer. They seem to get > > lost in the IP/UDP Layer of the receiving box. > > > > We have got the following configuration: > > Two linux boxes (P4, 733 MHz, 256 MB RAM, kernel 2.4.0) > > are directly connected with two syskonnect sk98xx > > gigabit ethernet cards. We are sending a file from one host to the other > > > > with UDP. About half of the file is lost in the receiving application. > > But according to the statistics in /proc/net/dev no errors (fifo, frame, > > dropped...) > > occured in the network layer. Even the transmitted and received > > data at the network layer (tx-bytes, -packets) are identical > > to the amount of the transfered file (plus network overhead). > > > > Doas anybody know where the loss occurs? Is there a loss at the > > network layer or in the higher protocol layers? > > UDP by default has 64K buffer and drops packets when it overflows. > You can check that using netstat -s. > You can increase it use the SO_{SND,RCV}BUF socket options and/or the > net/core/[rw]mem_* sysctls. > > -Andi > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > Please read the FAQ at http://www.tux.org/lkml/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/