From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 26 Jan 2001 13:09:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 26 Jan 2001 13:09:25 -0500 Received: from Cantor.suse.de ([194.112.123.193]:55563 "HELO Cantor.suse.de") by vger.kernel.org with SMTP id ; Fri, 26 Jan 2001 13:09:14 -0500 Date: Fri, 26 Jan 2001 19:08:56 +0100 From: Andi Kleen To: Martin Rauh Cc: linux-kernel@vger.kernel.org Subject: Re: Packet loss in IP/UDP Stack? Message-ID: <20010126190856.A19098@gruyere.muc.suse.de> In-Reply-To: <3A71BB68.21B998AB@gmx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <3A71BB68.21B998AB@gmx.de>; from martin.rauh@gmx.de on Fri, Jan 26, 2001 at 07:01:12PM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 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/