Also i have noticed, when TSO is disabled IPv4 TCP Performance also drops from ~10 Gb/s to ~3 Gb/s, the same as with IPv6. I have read threads from around 2010 about the networking stack not having support for TSO on IPv6 Packets. May this be the problem in this case?
> On 14 Jul 2015, at 23:44, Sydney Meyer <syd.me...@gmail.com> wrote: > > >> On 14 Jul 2015, at 18:15, Mark Felder <f...@freebsd.org> wrote: >> >> >> >> On Tue, Jul 14, 2015, at 07:36, Sydney Meyer wrote: >>> Hello everybody, >>> >>> i have noticed some odd behaviour with networking under Xen with FreeBSD >>> 10 as a DomU. >>> >>> - IPv6 (TCP) bandwith drops from ~10 Gbit/s IPv4 to around 3 Gbit/s IPv6. >>> (measured with iperf) >>> >> >> What is the "before" and "after" here? When is FreeBSD successfully >> doing 10Gbit/s and when isn't it? Is pf enabled? Are you scrubbing? > > With two clean 10.1 AMD64 DomU installations both with a single, pinned cpu, > without pf enabled the TCP performance between the two hosts, measured with > iperf, differs between ~10 Gb/s on IPv4 and ~3 Gb/s on IPv6. With pf enabled > and "scrub in all" the difference is almost the same. >> >>> - Dropped/Stalled Connections with TCP Segmentation Offload and pf >>> enabled. >>> >> >> TSO is a known issue. I've been turning it off for years to get FreeBSD >> to play nice on Xen. > > This one i am still investigating, because it happens only in "certain" > situations (which are not clear to me, atm), but the host seems to drop ACK > Packets in some situations like when connected to via IPSEC or via double > NAT. This happens only when pf it actually enabled. Disabling TSO on the > xn-interface seems to help. >> >>> - IPSEC-enabled Kernel TCP Performance drops from ~10 Gbit/s to ~200 >>> Mbit/s (iperf). >>> >> >> Are you saying FreeBSD non-IPSEC kernel can do 10Gbit/s TCP performance, >> but IPSEC kernel immediately drops it to 200Mbit/s? > > As for the apparent performance drop with IPSEC enabled Kernels without > security associations installed, i am unable to reproduce this now, not on > 10.0 or 10.1 nor 10 STABLE. Only when actually _using_ IPSec the performance > drops from ~10Gb/s to around ~200Mb/s whether actually encrypting esp traffic > or not. > This clearly must have been a mistake on my side, although i could have sworn > that i checked this two times before asking on the forums and the -net > mailing list a few weeks ago. Well then, i am sincerely sorry about this one. >> _______________________________________________ >> freebsd-xen@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-xen >> To unsubscribe, send any mail to "freebsd-xen-unsubscr...@freebsd.org" > _______________________________________________ freebsd-xen@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-xen To unsubscribe, send any mail to "freebsd-xen-unsubscr...@freebsd.org"
