Jochen, On Monday 18 May 2009, Jochen Roderburg wrote: > Zitat von Jochen Roderburg <[email protected]>: > > Situation on two systems (one at home, one at work): > > > > VirtualBox 2.2.0 > > Linux Host (Slackware-based with self-compiled stock kernel) > > Windows 2000 Guest > > Bridged networking > > > > Network Chips: > > on home system: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI > > Express Gigabit Ethernet controller > > on work system: Intel Corporation 82566DM-2 Gigabit Network Connection > > > > Everything works fine on both systems with Linux kernel 2.6.28 and > > also on the home system with 2.6.29. > > > > But with a 2.6.29 kernel on the work system the direct network > > connections between guest and host are extremely slow and not usable. > > Examples: > > A longer output in a terminal window comes with great pauses and > > eventually stalls. > > Filesystem connections to a samba server can't display large > > directory listings, in the samba log files I see timeout errors and > > frequent server restarts. > > > > Astonishingly at the same time connections from the guest to other > > remote systems work without problems. > > Seems I have to answer this myself. ;-) > > In short: it was a bug in the 2.6.29 kernel which is already repaired > in kernel version 2.6.29.2. > > More explanations: > > I wrote this question both in the vbox forum and here, but did not get > an answer in neither places. But in the forum some other people > reported problems which very much looked like the same and one person > had found the essential clue, namely that it had something to do with > the gso (generic segmentation offload) feature of the Linux kernel. > And with this information it was not difficult to google a redhat > bugzilla entry https://bugzilla.redhat.com/show_bug.cgi?id=490266 > where the whole problem was discussed, explained and solved. > > It was/is a bug in the linux kernel 2.6.29 which was triggered by the > tun driver (or perhaps the vbox netfilter in our cases) in connection > with nic drivers that use that gso feature. > > The (one-line) patch is now in the kernel sources since 2.6.29.2. > > So we have various solutions now: > 1) A workaround is to turn off the "segmentation offload" feature for > the nic (ethtool -K ethn tso off seems to do the trick). > 2) Add the one-line patch to your kernel sources yourself. > 3) Use a kernel version from 2.6.29.2 up. > > I have tested #2 now on my system and the network connections between > host and guest work fine again.
Thank you _very_ much for this information! Actually we saw several reports about this issue and we were able to reproduce it locally as well. Disabling the tso/gso feature with ethtool helped here but this isn't applicable of course. So far we assumed that this was due to some bug in our code but I was able reproduce the issue locally with 2.6.29.1 and can confirm that 2.6.29.3 restored the full speed. Thanks again, Frank -- Dr.-Ing. Frank Mehnert Sun Microsystems, Inc. www.sun.com
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