Re: Weird network performance problem

[Chavdar Ivanov <ci4ic4%gmail.com@localhost>]

From what I can see, the reason is

sysctl -w net.inet.tcp.{send|recv}space=131072

If I revert to 32768, I get back about the third of the speed.
net.inet.tcp.{send|recv}buf_auto doesn't seem to make any difference.

Thanks,

Chavdar



On Sun, 19 Jan 2020 at 18:29, Chavdar Ivanov <ci4ic4%gmail.com@localhost> wrote:
>
> On Sun, 19 Jan 2020 at 18:17, Jason Mitchell <jmitchel%bigjar.com@localhost> wrote:
> >
> ...
> >
> > First, Powerline adapters only get 1/7th the advertised speed. They send “1Gigabit” of data, but they’re really sending ~130Mbit of the same data 7 times because of how noisy power cabling is.
>
> Yes, I am aware - that's around what I am getting here. I have another
> W10 machine on the same switch as the NetBSD box I did the tests with.
>
> >
> > Second, try adding -l 9000 to your iperf3 tests. The Linux distributions I’ve used have this as the default and I’ve noticed big speed improvements doing this, but I have no clue why it works.
>
> Yes, this appears to improve the speed a bit more - now I am getting
>
> Connecting to host ymir, port 5201
> [  4] local 192.168.0.36 port 1236 connected to 192.168.0.29 port 5201
> [ ID] Interval           Transfer     Bandwidth
> [  4]   0.00-1.00   sec   107 MBytes   901 Mbits/sec
> [  4]   1.00-2.00   sec   111 MBytes   934 Mbits/sec
> [  4]   2.00-3.00   sec   103 MBytes   867 Mbits/sec
> [  4]   3.00-4.00   sec  84.7 MBytes   710 Mbits/sec
> [  4]   4.00-5.00   sec  89.5 MBytes   751 Mbits/sec
> [  4]   5.00-6.00   sec  86.6 MBytes   727 Mbits/sec
> [  4]   6.00-7.00   sec   103 MBytes   864 Mbits/sec
> [  4]   7.00-8.00   sec   110 MBytes   919 Mbits/sec
> [  4]   8.00-9.00   sec   109 MBytes   917 Mbits/sec
> [  4]   9.00-10.00  sec   108 MBytes   903 Mbits/sec
> - - - - - - - - - - - - - - - - - - - - - - - - -
> [ ID] Interval           Transfer     Bandwidth
> [  4]   0.00-10.00  sec  1013 MBytes   849 Mbits/sec                  sender
> [  4]   0.00-10.00  sec  1012 MBytes   849 Mbits/sec                  receiver
>
> iperf Done.
>
>
> >
> > Thanks,
> >
> > Jason M.
> >
> > Sent from my iPhone
>
>
>
> --
> ----



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