[WireGuard] heavy packet loss

[k at vodka.home.kg]

Problematic version was 0.0.20161025.
I upgraded kmod to 0.0.20161103 at it works fine now.

> Hi k,

> I'll look into this. Which snapshot are you using? Or, which commit is this?

> Jason


> On Fri, Nov 4, 2016 at 5:01 PM,  <k at vodka.home.kg> wrote:
>> I'm trying to connect 2 endpoints with wireguard.
>> One endpoint has MTU of inet inteface 1500, another 1456.
>> To prevent packet fragmentation on inet interface i set up mtu 1383 for both wg interfaces. Checked that no frag occurs on inet interface in wireshark. Maximum packet data size is 1383-28 = 1355. Checked with no-fragment ping, packets pass well.
>>
>> First I checked packet loss between inet IPs
>>
>> iperf  -c x.x.x.x -u -b 25M -l 1400
>> 0.0-10.3 sec  29.6 MBytes  24.2 Mbits/sec  16.073 ms  175/23090 (0.76%)
>>
>> packet loss always within 0.5..1%. its normal
>> now I try to do the same with much less bandwidth between wireguard ips
>> on packet size <=1252 packet loss rate is 0.5..1%
>>
>> iperf  -c 192.168.254.65 -w 500000 -u -b 1M -l 1252
>> 0.0-10.0 sec  1.18 MBytes   991 Kbits/sec   0.659 ms    9/ 1000 (0.9%)
>>
>> but starting from packet size 1253 packets loss greatly increases. its 6..10%
>>
>> iperf  -c 192.168.254.65 -w 500000 -u -b 1M -l 1253
>> 0.0-10.0 sec  1.12 MBytes   936 Kbits/sec   0.328 ms   64/  998 (6.4%)
>>
>> Thats why TCP is incredibly slow. If I set up mss for TCP to not exceed packets size threshold TCP is fast.
>>
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-- 
С уважением,
 K                          mailto:k at vodka.home.kg