Date: Tue, 16 Mar 2021 15:35:25 +0100 From: tuexen@freebsd.org To: Marek Zarychta <zarychtam@plan-b.pwste.edu.pl> Cc: Blake Hartshorn <contact@blakehartshorn.com>, freebsd-net@freebsd.org Subject: Re: Severe IPv6 TCP transfer issues on 13.0-RC1 and RC2 Message-ID: <947D1E51-CCB0-4A1E-B671-708F70420DA1@freebsd.org> In-Reply-To: <d71bd76f-d01a-0af7-9b02-c3a473de5ef9@plan-b.pwste.edu.pl> References: <5753280.1HxCrU2fYu@thinkbook> <E1346D9D-F1E0-4ABC-89D6-33BC77705771@freebsd.org> <10847992.4GmZMkJedg@thinkbook> <2808496E-C2B5-4B6F-8FDB-310B7F69E540@freebsd.org> <d71bd76f-d01a-0af7-9b02-c3a473de5ef9@plan-b.pwste.edu.pl>
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> On 16. Mar 2021, at 15:18, Marek Zarychta =
<zarychtam@plan-b.pwste.edu.pl> wrote:
>=20
> W dniu 16.03.2021 o 12:50, tuexen@freebsd.org pisze:
>>> On 16. Mar 2021, at 11:55, Blake Hartshorn =
<contact@blakehartshorn.com> wrote:
>>>=20
>>> Hi Michael,
>>>=20
>>> I've attached tcpdumps for port 80 on both sides of a bad transfer, =
using 2 VMs in the same datacenter, FreeBSD 13 serving and 12 as a =
client. A friend of mine suggested I also run some tests with iperf3, so =
pasting those results below. You'll see it going fast in one direction =
and crawling in the other on TCP. There's also some disparity on UDP.=20
>> The problem is that the server provides TCP segments larger than the =
MTU
>> to the NIC. These are dropped and needs to be retransmitted. That is =
why
>> it takes so long. So I guess TSO is enabled on the NIC and not =
working correctly.
>>=20
>> What is the output of ifconfig? Can you disable TSO? Does that work =
around
>> the problem?
>>=20
>> Best regards
>> Michael
>>>=20
>>> TCP:
>>> [ ID][Role] Interval Transfer Bitrate Retr =
Cwnd
>>> [ 5][TX-C] 0.00-1.00 sec 27.7 MBytes 233 Mbits/sec 342 =
26.7 KBytes =20
>>> [ 7][RX-C] 0.00-1.00 sec 4.18 KBytes 34.3 Kbits/sec =
=20
>>> [ 5][TX-C] 1.00-2.00 sec 15.8 MBytes 132 Mbits/sec 249 =
52.0 KBytes =20
>>> [ 7][RX-C] 1.00-2.00 sec 4.18 KBytes 34.3 Kbits/sec =
=20
>>> [ 5][TX-C] 2.00-3.00 sec 13.7 MBytes 115 Mbits/sec 307 =
15.4 KBytes =20
>>> [ 7][RX-C] 2.00-3.00 sec 4.18 KBytes 34.3 Kbits/sec =
=20
>>> [ 5][TX-C] 3.00-4.00 sec 14.5 MBytes 121 Mbits/sec 260 =
22.4 KBytes =20
>>> [ 7][RX-C] 3.00-4.00 sec 4.18 KBytes 34.3 Kbits/sec =
=20
>>> [ 5][TX-C] 4.00-5.00 sec 14.3 MBytes 120 Mbits/sec 240 =
37.9 KBytes =20
>>> [ 7][RX-C] 4.00-5.00 sec 5.58 KBytes 45.7 Kbits/sec =
=20
>>> [ 5][TX-C] 5.00-6.00 sec 17.7 MBytes 149 Mbits/sec 363 =
15.4 KBytes =20
>>> [ 7][RX-C] 5.00-6.00 sec 4.18 KBytes 34.3 Kbits/sec =
=20
>>> [ 5][TX-C] 6.00-7.00 sec 14.8 MBytes 124 Mbits/sec 287 =
8.38 KBytes =20
>>> [ 7][RX-C] 6.00-7.00 sec 5.58 KBytes 45.7 Kbits/sec =
=20
>>> [ 5][TX-C] 7.00-8.00 sec 14.7 MBytes 123 Mbits/sec 293 =
28.1 KBytes =20
>>> [ 7][RX-C] 7.00-8.00 sec 4.18 KBytes 34.3 Kbits/sec =
=20
>>> [ 5][TX-C] 8.00-9.00 sec 11.9 MBytes 100 Mbits/sec 325 =
18.3 KBytes =20
>>> [ 7][RX-C] 8.00-9.00 sec 4.18 KBytes 34.3 Kbits/sec =
=20
>>> [ 5][TX-C] 9.00-10.00 sec 14.3 MBytes 120 Mbits/sec 315 =
39.3 KBytes =20
>>> [ 7][RX-C] 9.00-10.00 sec 4.18 KBytes 34.3 Kbits/sec =
=20
>>> - - - - - - - - - - - - - - - - - - - - - - - - -
>>> [ ID][Role] Interval Transfer Bitrate Retr
>>> [ 5][TX-C] 0.00-10.00 sec 159 MBytes 134 Mbits/sec 2981 =
sender
>>> [ 5][TX-C] 0.00-10.00 sec 159 MBytes 134 Mbits/sec =
receiver
>>> [ 7][RX-C] 0.00-10.00 sec 77.0 KBytes 63.1 Kbits/sec 65 =
sender
>>> [ 7][RX-C] 0.00-10.00 sec 44.6 KBytes 36.6 Kbits/sec =
receiver
>>> =
--------------------------------------------------------------------------=
---------------------------------
>>>=20
>>>=20
>>> UDP:
>>> [ ID][Role] Interval Transfer Bitrate Jitter =
Lost/Total Datagrams
>>> [ 5][TX-C] 0.00-1.00 sec 81.6 MBytes 685 Mbits/sec =
67798 =20
>>> [ 7][RX-C] 0.00-1.00 sec 8.80 MBytes 73.8 Mbits/sec 0.255 ms =
54070/60475 (89%) =20
>>> [ 5][TX-C] 1.00-2.00 sec 72.7 MBytes 610 Mbits/sec =
64802 =20
>>> [ 7][RX-C] 1.00-2.00 sec 8.52 MBytes 71.5 Mbits/sec 0.154 ms =
68912/75116 (92%) =20
>>> [ 5][TX-C] 2.00-3.00 sec 73.7 MBytes 618 Mbits/sec =
64158 =20
>>> [ 7][RX-C] 2.00-3.00 sec 8.52 MBytes 71.5 Mbits/sec 0.276 ms =
67738/73945 (92%) =20
>>> [ 5][TX-C] 3.00-4.00 sec 76.6 MBytes 643 Mbits/sec =
63521 =20
>>> [ 7][RX-C] 3.00-4.00 sec 8.55 MBytes 71.8 Mbits/sec 0.160 ms =
68647/74874 (92%) =20
>>> [ 5][TX-C] 4.00-5.00 sec 76.1 MBytes 638 Mbits/sec =
64614 =20
>>> [ 7][RX-C] 4.00-5.00 sec 8.55 MBytes 71.7 Mbits/sec 0.461 ms =
67542/73767 (92%) =20
>>> [ 5][TX-C] 5.00-6.00 sec 75.9 MBytes 637 Mbits/sec =
64834 =20
>>> [ 7][RX-C] 5.00-6.00 sec 8.57 MBytes 71.9 Mbits/sec 0.297 ms =
71565/77806 (92%) =20
>>> [ 5][TX-C] 6.00-7.00 sec 73.0 MBytes 613 Mbits/sec =
63639 =20
>>> [ 7][RX-C] 6.00-7.00 sec 8.40 MBytes 70.5 Mbits/sec 0.199 ms =
69545/75663 (92%) =20
>>> [ 5][TX-C] 7.00-8.00 sec 74.6 MBytes 626 Mbits/sec =
65030 =20
>>> [ 7][RX-C] 7.00-8.00 sec 8.78 MBytes 73.6 Mbits/sec 0.254 ms =
67173/73566 (91%) =20
>>> [ 5][TX-C] 8.00-9.00 sec 75.0 MBytes 629 Mbits/sec =
64848 =20
>>> [ 7][RX-C] 8.00-9.00 sec 8.77 MBytes 73.5 Mbits/sec 0.298 ms =
70932/77315 (92%) =20
>>> [ 5][TX-C] 9.00-10.00 sec 74.5 MBytes 625 Mbits/sec =
64487 =20
>>> [ 7][RX-C] 9.00-10.00 sec 8.71 MBytes 73.1 Mbits/sec 0.185 ms =
68268/74612 (91%) =20
>>> - - - - - - - - - - - - - - - - - - - - - - - - -
>>> [ ID][Role] Interval Transfer Bitrate Jitter =
Lost/Total Datagrams
>>> [ 5][TX-C] 0.00-10.00 sec 754 MBytes 632 Mbits/sec 0.000 ms =
0/647731 (0%) sender
>>> [ 5][TX-C] 0.00-10.12 sec 105 MBytes 87.2 Mbits/sec 0.245 ms =
571090/647649 (88%) receiver
>>> [ 7][RX-C] 0.00-10.00 sec 1009 MBytes 846 Mbits/sec 0.000 ms =
0/761013 (0%) sender
>>> [ 7][RX-C] 0.00-10.12 sec 86.2 MBytes 71.4 Mbits/sec 0.185 ms =
674392/737139 (91%) receiver
>>>=20
>>>=20
>=20
> Taking a look at this iperf output I recalled that 80% of my setups
> suffered from similar issue after transitioning from 1{1,2}-STABLE to
> 13-STABLE about a mounth ago. I have asked on IRC but nobody confirmed
> similar problems so I have reduced MTU to 8900 from the original 9000 =
on
> some vlan(4) interfaces to solve the issue. I am using mostly vlan(4)s
> over LACP lagg(4)s created on NICs. So far (for FreeBSD 11 and 12)
> setting MTU 9000 on physical NIC was sufficient to make it work, now I
> have set MTU 9000 on NICs and reduced MTU 8900 on vlan(4)s.
TCP announces an MSS of 1440, which corresponds to an MTU of 1500 byte.
So I guess your problem is different.
Is your physical MTU 9000 bytes?
Best regards
Michael
>=20
>>>=20
>>>=20
>>> On Tuesday, March 16, 2021 4:16:15 AM EDT tuexen@freebsd.org wrote:
>>>>> On 15. Mar 2021, at 12:56, Blake Hartshorn =
<contact@blakehartshorn.com> wrote:
>>>>>=20
>>>>> The short version, when I use FreeBSD 13, delivering data can take =
5 minutes for 1MB over SSH or HTTP when using IPv6. This problem does =
not happen with IPv4. I installed FreeBSD 12 and Linux on that same =
device, neither had the problem.
>>>>>=20
>>>>> Did some troubleshooting with Linode, have ultimately ruled the =
network itself out at this point. When the server is on FreeBSD 13, it =
can download quickly over IPv6, but not deliver. Started investigating =
after noticing my SSH session was lagging when cat'ing large files or =
running builds. This problem even occurs between VMs in the same =
datacenter. I generated a 1MB file of base64 garbage served by nginx for =
testing. IPv6 is being configured by SLAAC and on both 12 and 13 =
installs was setup by the installer. Linode uses Linux/KVM hosts for =
their virtual machines so it's running on that virtual adapter.
>>>>>=20
>>>>> I asked on the forums, another user recommended going to the =
mailing lists instead. Does anyone know if config settings need to be =
different on 13? Did I maybe just find a real issue? I can provide any =
requested details. Thanks!
>>>> Could you prove a .pcap tracefile, one from the sender, one from =
the recevier, of
>>>> a TCP/IPv6 connection, which doesn't work as expected. For example, =
use your 1MB
>>>> base64 garbage transfer.
>>>>=20
>>>> Best regardes
>>>> Michael
>>>>>=20
>>>>>=20
>>>>> _______________________________________________
>>>>> freebsd-net@freebsd.org mailing list
>>>>> https://lists.freebsd.org/mailman/listinfo/freebsd-net
>>>>> To unsubscribe, send any mail to =
"freebsd-net-unsubscribe@freebsd.org"
>>>>=20
>>>>=20
>>> <freebsd12-client.pcap.gz><freebsd13-server.pcap.gz>
>>=20
>> _______________________________________________
>> freebsd-net@freebsd.org mailing list
>> https://lists.freebsd.org/mailman/listinfo/freebsd-net
>> To unsubscribe, send any mail to =
"freebsd-net-unsubscribe@freebsd.org"
>>=20
>=20
>=20
> --=20
> Marek Zarychta
>=20
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