From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peri Hankey Subject: Re: network hang trigger Date: Wed, 15 Sep 2004 09:38:50 +0100 Sender: xen-devel-admin@lists.sourceforge.net Message-ID: <4147FF9A.4060307@thegreen.co.uk> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Errors-To: xen-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: James Harper Cc: xen-devel@lists.sourceforge.net List-Id: xen-devel@lists.xenproject.org James I can confirm that your problem occurs in xen-2.0-20040914. In this example a4.local is the xen0 machine (2.6.8.1-xen0), a30 is one of several xenU guests on a4 (all 2.6.8.1-xenU). First a simple ping, which works OK. Then your special poison ping: nasty pause, and possibly useful messages. [administrator@a30 administrator]$ ping a4.local PING a4.local (192.168.0.4) 56(84) bytes of data. 64 bytes from a4.local (192.168.0.4): icmp_seq=1 ttl=64 time=5.72 ms 64 bytes from a4.local (192.168.0.4): icmp_seq=2 ttl=64 time=0.150 ms --- a4.local ping statistics --- 2 packets transmitted, 2 received, 0% packet loss, time 1010ms rtt min/avg/max/mdev = 0.150/2.937/5.724/2.787 ms [administrator@a30 administrator]$ ping -s 1473 a4.local PING a4.local (192.168.0.4) 1473(1501) bytes of data. ping: sendmsg: No buffer space available ping: sendmsg: No buffer space available ping: sendmsg: No buffer space available ping: sendmsg: No buffer space available ping: sendmsg: No buffer space available ping: sendmsg: No buffer space available ping: sendmsg: No buffer space available From 192.168.0.4 icmp_seq=1 Frag reassembly time exceeded 1481 bytes from 192.168.0.4: icmp_seq=2 ttl=64 time=28980 ms 1481 bytes from 192.168.0.4: icmp_seq=3 ttl=64 time=27980 ms 1481 bytes from a4.local (192.168.0.4): icmp_seq=4 ttl=64 time=26980 ms --- a4.local ping statistics --- 11 packets transmitted, 3 received, +1 errors, 72% packet loss, time 29287ms rtt min/avg/max/mdev = 26980.569/27980.589/28980.612/816.525 ms, pipe 11 I hope that helps. Peri James Harper wrote: >I have found that simply doing a ping with packetsize > 1500 (maybe >mtu???) causes the network to hang for a short time. This is from xenU >and xen0 on the same machine. > >Can someone else _please_ test this? I am able to make the network hang >by saying from domU: >ping -s 1473 >(1473 + 28 byte header = 1501 byte packet) > >I'll do more testing tomorrow. > >thanks > >James > > >------------------------------------------------------- >This SF.Net email is sponsored by: thawte's Crypto Challenge Vl >Crack the code and win a Sony DCRHC40 MiniDV Digital Handycam >Camcorder. More prizes in the weekly Lunch Hour Challenge. >Sign up NOW http://ad.doubleclick.net/clk;10740251;10262165;m >_______________________________________________ >Xen-devel mailing list >Xen-devel@lists.sourceforge.net >https://lists.sourceforge.net/lists/listinfo/xen-devel > > > > ------------------------------------------------------- This SF.Net email is sponsored by: thawte's Crypto Challenge Vl Crack the code and win a Sony DCRHC40 MiniDV Digital Handycam Camcorder. More prizes in the weekly Lunch Hour Challenge. Sign up NOW http://ad.doubleclick.net/clk;10740251;10262165;m