From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Baptiste Favre Subject: Re: PCI passthrough issue Date: Thu, 13 Jan 2011 20:18:33 +0100 Message-ID: <4D2F5009.2090701@jbfavre.org> References: <4D2DCB09.5010703@jbfavre.org> <20110112154344.GA28780@dumpdata.com> <4D2DCE8F.3060504@jbfavre.org> <20110112163647.GB10863@dumpdata.com> <4D2DDD4D.9090503@jbfavre.org> <20110112172620.GB11522@dumpdata.com> <4D2DE889.4040604@jbfavre.org> <20110112183242.GA23125@dumpdata.com> <4D2E0A02.2020606@jbfavre.org> <20110112214034.GA5833@dumpdata.com> <4D2E2149.1010002@jbfavre.org> <4D2E28C5.30203@jbfavre.org> <4D2EE1DE.5070006@jbfavre.org> Reply-To: xen-devel@lists.xensource.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <4D2EE1DE.5070006@jbfavre.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Hello, My dom0 is back and I performed some more tests. I told in my first mail that ping works. Indeed it works, but not always: # ping -c2 10.0.0.1 PING 10.0.0.1 (10.0.0.1): 56 data bytes 64 bytes from 10.0.0.1: seq=3D0 ttl=3D64 time=3D0.846 ms 64 bytes from 10.0.0.1: seq=3D1 ttl=3D64 time=3D0.824 ms --- 10.0.0.1 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max =3D 0.824/0.835/0.846 ms # ping -c2 -s60 10.0.0.1 PING 10.0.0.1 (10.0.0.1): 60 data bytes 68 bytes from 10.0.0.1: seq=3D0 ttl=3D64 time=3D0.819 ms 68 bytes from 10.0.0.1: seq=3D1 ttl=3D64 time=3D0.807 ms --- 10.0.0.1 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max =3D 0.807/0.813/0.819 ms Increasing packet size is ok until this one: # ping -c2 -s85 10.0.0.1 PING 10.0.0.1 (10.0.0.1): 85 data bytes 93 bytes from 10.0.0.1: seq=3D0 ttl=3D64 time=3D0.823 ms 93 bytes from 10.0.0.1: seq=3D1 ttl=3D64 time=3D0.816 ms --- 10.0.0.1 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max =3D 0.816/0.819/0.823 ms root@OpenWrt:/# ping -c2 -s86 10.0.0.1 PING 10.0.0.1 (10.0.0.1): 86 data bytes --- 10.0.0.1 ping statistics --- 2 packets transmitted, 0 packets received, 100% packet loss As you see, packet size seems to be limited in a way. From another machine on the same LAN I can do ping -s1500 without any problem. So I think I hit a bug. Either it's Xen related, or Debian (through debian kernel version). Now the question is: how can I determine which part is responsible ? Regards, JB Le 13/01/2011 12:28, Jean Baptiste Favre a =E9crit : > Have had a look on both tcpdump captures. > 1. From the OpenWRT domU: nothing special. Lot of STP traffic due to my > network architecture. Don't thing this could be the cause of my problem > since I'm always able to reproduce the failure whatever could be the > order of DNS requests. Don't see "big" DNS answers coming in, see > multiple requests before timeout. >=20 > 2. From my gateway: nothing special here too. Same STP traffic (have > checked GW network setup as well). See each DNS requests my domU sent > and can see as well answers, which are not received by domU. No strange > ARP traffic. >=20 > I wanted to change the network, thinking about a bogus driver (never > know). My Dom0 has crashed during reboot and I've no way to remotely > reboot it (no remote power control and it seems that Magic SysRQ are no= t > transfered through my Putty/screen connection). >=20 > Will reboot it when at home and continue investigation with another > network card and maybe another operating system to check if bad > behaviour is still there. >=20 > Regards, > JB