Date: Sun, 19 Jul 2015 21:22:24 +0200 From: Sydney Meyer <syd.meyer@gmail.com> To: freebsd-xen@freebsd.org Subject: Re: Networking under Xen Message-ID: <41967713-C2DE-4657-96ED-F8BE3491D4EA@gmail.com> In-Reply-To: <4B6D4AEF-6107-4F95-9F5A-F0EA137809AC@gmail.com> References: <4E7B7075-4E0D-4EA7-9F5D-6D252CFBD487@gmail.com> <1436890526.3162974.323521249.6B73E6E2@webmail.messagingengine.com> <4B6D4AEF-6107-4F95-9F5A-F0EA137809AC@gmail.com>
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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.meyer@gmail.com> wrote: >=20 >=20 >> On 14 Jul 2015, at 18:15, Mark Felder <feld@FreeBSD.org> wrote: >>=20 >>=20 >>=20 >> On Tue, Jul 14, 2015, at 07:36, Sydney Meyer wrote: >>> Hello everybody, >>>=20 >>> i have noticed some odd behaviour with networking under Xen with = FreeBSD >>> 10 as a DomU. >>>=20 >>> - IPv6 (TCP) bandwith drops from ~10 Gbit/s IPv4 to around 3 Gbit/s = IPv6. >>> (measured with iperf) >>>=20 >>=20 >> 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? >=20 > 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. >>=20 >>> - Dropped/Stalled Connections with TCP Segmentation Offload and pf >>> enabled. >>>=20 >>=20 >> TSO is a known issue. I've been turning it off for years to get = FreeBSD >> to play nice on Xen. >=20 > 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. >>=20 >>> - IPSEC-enabled Kernel TCP Performance drops from ~10 Gbit/s to ~200 >>> Mbit/s (iperf). >>>=20 >>=20 >> Are you saying FreeBSD non-IPSEC kernel can do 10Gbit/s TCP = performance, >> but IPSEC kernel immediately drops it to 200Mbit/s? >=20 > 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-unsubscribe@freebsd.org" >=20
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