perfSONAR User Q&A and Other Discussion

[Brian Candler <>]

So, an interesting development.

It turns out that in our office network, the provider is blocking 
inbound packets with udp src 123 dst 123. Hence things aren't as 
ntp-sync'd as they should be.

Using "ntpdate -u" (unprivileged source port) I can get the clocks into 
better sync. After doing this, bwctl -s and -c are both running. Hence I 
think that bwctl is very sensitive to clock drift, and is dying if the 
clocks are too far apart. (Maybe I have an opportunity here to dig down 
and find the underlying problem?)

But: using bwctl I am still getting lower figures than iperf3 by itself. 
What flags or options is bwctl running iperf3 with?

bou-perf-1 ~]$ bwctl -s cov-perf-1 -T iperf3
bwctl: Using tool: iperf3
bwctl: 16 seconds until test results available

SENDER START
Connecting to host 192.0.2.251, port 5252
[ 16] local 192.0.2.254 port 39837 connected to 192.0.2.251 port 5252
[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[ 16]   0.00-1.00   sec   693 MBytes  5.79 Gbits/sec    0    559 KBytes
[ 16]   1.00-2.00   sec   790 MBytes  6.65 Gbits/sec    0    621 KBytes
[ 16]   2.00-3.00   sec   831 MBytes  6.97 Gbits/sec    0    669 KBytes
[ 16]   3.00-4.00   sec   830 MBytes  6.96 Gbits/sec    0    700 KBytes
[ 16]   4.00-5.00   sec   832 MBytes  6.98 Gbits/sec    0    721 KBytes
[ 16]   5.00-6.00   sec   835 MBytes  6.99 Gbits/sec    0    764 KBytes
[ 16]   6.00-7.00   sec   754 MBytes  6.33 Gbits/sec    0    786 KBytes
[ 16]   7.00-8.00   sec   941 MBytes  7.91 Gbits/sec    0    813 KBytes
[ 16]   8.00-9.00   sec   787 MBytes  6.58 Gbits/sec    0    840 KBytes
[ 16]   9.00-10.00  sec   757 MBytes  6.36 Gbits/sec    0    854 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[ 16]   0.00-10.00  sec  7.86 GBytes  6.75 Gbits/sec 0             sender
[ 16]   0.00-10.00  sec  7.86 GBytes  6.75 Gbits/sec                  
receiver

iperf Done.

SENDER END
bou-perf-1 ~]$ bwctl -c cov-perf-1 -T iperf3
bwctl: Using tool: iperf3
bwctl: 16 seconds until test results available

SENDER START
Connecting to host 192.0.2.254, port 5012
[ 16] local 192.0.2.251 port 34421 connected to 192.0.2.254 port 5012
[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[ 16]   0.00-1.00   sec   687 MBytes  5.75 Gbits/sec    0    512 KBytes
[ 16]   1.00-2.00   sec   851 MBytes  7.15 Gbits/sec    0    574 KBytes
[ 16]   2.00-3.00   sec  1.00 GBytes  8.61 Gbits/sec    0    632 KBytes
[ 16]   3.00-4.00   sec  1.00 GBytes  8.61 Gbits/sec    0    689 KBytes
[ 16]   4.00-5.00   sec   933 MBytes  7.83 Gbits/sec    0    737 KBytes
[ 16]   5.00-6.00   sec   922 MBytes  7.74 Gbits/sec    0    775 KBytes
[ 16]   6.00-7.00   sec   835 MBytes  7.00 Gbits/sec    0    803 KBytes
[ 16]   7.00-8.00   sec   843 MBytes  7.07 Gbits/sec    0    814 KBytes
[ 16]   8.00-9.00   sec   840 MBytes  7.03 Gbits/sec    0    834 KBytes
[ 16]   9.00-10.00  sec   903 MBytes  7.57 Gbits/sec    0    871 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[ 16]   0.00-10.00  sec  8.66 GBytes  7.44 Gbits/sec 0             sender
[ 16]   0.00-10.00  sec  8.66 GBytes  7.44 Gbits/sec                  
receiver

iperf Done.

SENDER END
bou-perf-1 ~]$

Compared with:

bou-perf-1 ~]$ iperf3 -c cov-perf-1
Connecting to host cov-perf-1, port 5201
[  4] local 192.0.2.251 port 58192 connected to 192.0.2.254 port 5201
[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[  4]   0.00-1.00   sec   772 MBytes  6.47 Gbits/sec    0    601 KBytes
[  4]   1.00-2.00   sec  1.01 GBytes  8.64 Gbits/sec    0    653 KBytes
[  4]   2.00-3.00   sec  1.01 GBytes  8.65 Gbits/sec    0    714 KBytes
[  4]   3.00-4.00   sec  1.01 GBytes  8.65 Gbits/sec    0    757 KBytes
[  4]   4.00-5.00   sec  1.01 GBytes  8.64 Gbits/sec    0    799 KBytes
[  4]   5.00-6.00   sec  1.00 GBytes  8.63 Gbits/sec    0    831 KBytes
[  4]   6.00-7.00   sec  1.00 GBytes  8.63 Gbits/sec    0    870 KBytes
[  4]   7.00-8.00   sec  1.00 GBytes  8.63 Gbits/sec    0    884 KBytes
[  4]   8.00-9.00   sec  1.00 GBytes  8.63 Gbits/sec    0    904 KBytes
[  4]   9.00-10.00  sec  1.00 GBytes  8.62 Gbits/sec    0    943 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec  9.80 GBytes  8.42 Gbits/sec 0             sender
[  4]   0.00-10.00  sec  9.80 GBytes  8.42 Gbits/sec                  
receiver

iperf Done.

Regards,

Brian.