From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Andrews Subject: Re: network hang trigger Date: Wed, 15 Sep 2004 11:48:22 +0100 Sender: xen-devel-admin@lists.sourceforge.net Message-ID: <41481DF6.9080204@nodnol.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; 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: xen-devel@lists.sourceforge.net List-Id: xen-devel@lists.xenproject.org I'm seeing this problem: 81.187.70.17 is a secondary on DOM0's bridge. The host 'uml18' is DOM1. uml18:~# ping -s 2473 81.187.70.17 PING 81.187.70.17 (81.187.70.17) 2473(2501) bytes of data. 2481 bytes from 81.187.70.17: icmp_seq=1 ttl=64 time=0.559 ms .. time passes, I hit ^C .. 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 2481 bytes from 81.187.70.17: icmp_seq=6 ttl=64 time=30297 ms --- 81.187.70.17 ping statistics --- 12 packets transmitted, 2 received, 83% packet loss, time 34627ms rtt min/avg/max/mdev = 0.559/15149.215/30297.872/15148.657 ms, pipe 7 DOM0 has 384M, DOM1 has 64M, MTU 1500 in both. Different packet sizes seem to trigger the bug more or less quickly -- I first tried with 2000 byte packets, and didn't see the problem, then I tried 2473, and saw the problem then. Trying 2000 bytes again did then show the problem. This is running Xen-2.0 from 4th September -- I can give a more recent version a try, but should I be able to turn on writable pagetables with current code, given I had problems with that option with the code I'm running now? Chris. Keir Fraser wrote: > I can't reproduce this. e.g., > [root@druid-0 root]# ping -s 2473 128.232.39.40 > PING 128.232.39.40 (128.232.39.40) 2473(2501) bytes of data. > 2481 bytes from 128.232.39.40: icmp_seq=0 ttl=64 time=0.074 ms > 2481 bytes from 128.232.39.40: icmp_seq=1 ttl=64 time=0.057 ms > 2481 bytes from 128.232.39.40: icmp_seq=2 ttl=64 time=0.055 ms > 2481 bytes from 128.232.39.40: icmp_seq=3 ttl=64 time=0.057 ms > > Both domains have 256MB memory. MTU for both is 1500. > > -- Keir > > >>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 > >  -=- MIME -=-  > 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 =3D 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 > _______________________________________________ > 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