Bug 202199 - packet forwarding in xen becomes slow
Summary: packet forwarding in xen becomes slow
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: 10.1-RELEASE
Hardware: amd64 Any
: --- Affects Some People
Assignee: freebsd-xen (Nobody)
Depends on:
Reported: 2015-08-09 12:38 UTC by Andrei
Modified: 2015-08-10 15:57 UTC (History)
2 users (show)

See Also:


Note You need to log in before you can comment on or make changes to this bug.
Description Andrei 2015-08-09 12:38:12 UTC
Sorry if duplicate, but I don't found any.
When running FreebBSD as guest on xen with 
options         XENHVM                  
device          xenpci
in kernel the packet forwarding becomes really slow, something near 5kb/s
I also tried to disable lro txcsum rxcsum tso with ifconfig but there was no effect.
Something like this was in maillist but without happy end.

Linux version on host system with this bug is 3.18.12-gentoo
Please specify if you need more information.
Comment 1 Sydney Meyer 2015-08-09 18:47:12 UTC
Probably duplicate of https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=188261
Comment 2 Sydney Meyer 2015-08-09 18:50:11 UTC
and/or: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=197344
Comment 3 Andrei 2015-08-09 20:59:11 UTC
(In reply to Sydney Meyer from comment #1)
Thank You for fast response.
I already tried to run ifconfix xn0 -txcsum -tso4 -lro with no effect.
FreeBSD guest used for openvpn with nat on pf(but seems pf has no effect there because I've also tried tried natd)
Clients machines for openvpn are with windows/linux/freebsd and there no difference. On all of them there performance drops with xn interface.
One more detail FreeBSD guest  running in HVM mode.

(In reply to Sydney Meyer from comment #2)
This I will test tomorrow when will be at work.
Comment 4 Andrei 2015-08-10 15:57:12 UTC
(In reply to Sydney Meyer from comment #2)
I've checked and behavior looks very similar to https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=197344
After disabling tx perfomance increased but when target server is far away from FreeBSD box then degradation is the same.
For example if I will try to fetch something that is near to DC where guest system is than all is fine and speed is great  but if I will try to access thru vpn something that is in Asia(for example) the speed is really low.
Maybe tcp window somehow cutted and as a result I have low speed on big distances.
P.S. Sorry for my English)