perfSONAR User Q&A and Other Discussion

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Hello

I installed a perfsonar server and I've been facing similar problems with
bandwidth measurement, see below. I also set the MTU to different sizes (the
test below is with MTU=1400), but that did not seem to make a difference.
Occasionally, the tests do actually succeed (although the reported speed is
rather low - around 200Mbps for a Gb network and uplink).

Any thoughts about what could be the problem?

Best regards
Bogdan

----

bwctl -T iperf3 -t 10 -O 4 -v -x -c "perfsonar-bandwidth.esc.qmul.ac.uk:4823"
Messages being sent to syslog(user,err)
bwctl: Using 141.163.170.165 as the address for local sender
bwctl: Using perfsonar-bandwidth.esc.qmul.ac.uk:4823 as the address for remote
receiver
bwctl: Available in-common: iperf nuttcp iperf3
bwctl: Using tool: iperf3
bwctl: Server 'perfsonar-bandwidth.esc.qmul.ac.uk:4823' accepted test request
at time 1464087718.423526
bwctl: Client 'localhost' accepted test request at time 1464087735.082031
bwctl: Tests accepted at different times re-requesting test with new time
bwctl: Server 'perfsonar-bandwidth.esc.qmul.ac.uk:4823' accepted test request
at time 1464087740.078125
bwctl: Client 'localhost' accepted test request at time 1464087740.078125

RECEIVER START
bwctl: start_endpoint: 3673076511.268639
bwctl: run_endpoint: receiver: 194.36.11.37
bwctl: run_endpoint: sender: 141.163.170.165
bwctl: exec_line: iperf3 -s -1 -B 194.36.11.37 -f m -p 5656 -V
bwctl: run_tool: tester: iperf3
bwctl: run_tool: receiver: 194.36.11.37
bwctl: run_tool: sender: 141.163.170.165
bwctl: start_tool: 3673076537.000126
iperf 3.1.2
Linux perfsonar-bandwidth.esc.qmul.ac.uk 2.6.32-573.26.1.el6.web100.x86_64 #1
SMP Fri May 6 11:17:16 PDT 2016 x86_64
-----------------------------------------------------------
Server listening on 5656
-----------------------------------------------------------
Time: Tue, 24 May 2016 11:02:20 GMT
Accepted connection from 141.163.170.165, port 47577
     Cookie: localhost.localdomain.1464087740.079
     TCP MSS: 1368 (default)
[ 16] local 194.36.11.37 port 5656 connected to 141.163.170.165 port 47616
Starting Test: protocol: TCP, 1 streams, 131072 byte blocks, omitting 4
seconds, 10 second test
[ ID] Interval           Transfer     Bandwidth
[ 16]   0.00-1.00   sec  8.23 MBytes  69.0 Mbits/sec
(omitted)
[ 16]   1.00-2.00   sec  0.00 Bytes  0.00 Mbits/sec                  (omitted)
[ 16]   2.00-3.00   sec  0.00 Bytes  0.00 Mbits/sec                  (omitted)
[ 16]   3.00-4.00   sec  0.00 Bytes  0.00 Mbits/sec                  (omitted)
[ 16]   0.00-1.00   sec  0.00 Bytes  0.00 Mbits/sec
[ 16]   1.00-2.00   sec  0.00 Bytes  0.00 Mbits/sec
[ 16]   2.00-3.00   sec  0.00 Bytes  0.00 Mbits/sec
[ 16]   3.00-4.00   sec  0.00 Bytes  0.00 Mbits/sec
[ 16]   4.00-5.00   sec  0.00 Bytes  0.00 Mbits/sec
[ 16]   5.00-6.00   sec  0.00 Bytes  0.00 Mbits/sec
[ 16]   6.00-7.00   sec  0.00 Bytes  0.00 Mbits/sec
[ 16]   7.00-8.00   sec  0.00 Bytes  0.00 Mbits/sec
[ 16]   8.00-9.00   sec  0.00 Bytes  0.00 Mbits/sec
[ 16]   9.00-10.00  sec  0.00 Bytes  0.00 Mbits/sec
[ 16]  10.00-10.04  sec  0.00 Bytes  0.00 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
Test Complete. Summary Results:
[ ID] Interval           Transfer     Bandwidth
[ 16]   0.00-10.04  sec  0.00 Bytes  0.00 Mbits/sec                  sender
[ 16]   0.00-10.04  sec  0.00 Bytes  0.00 Mbits/sec                  receiver
CPU Utilization: local/receiver 0.1% (0.0%u/0.2%s), remote/sender 0.0%
(0.0%u/0.0%s)
bwctl: stop_tool: 3673076554.303890
bwctl: stop_endpoint: 3673076554.303890

RECEIVER END

SENDER START
bwctl: start_endpoint: 3673076511.272606
bwctl: run_endpoint: receiver: 194.36.11.37
bwctl: run_endpoint: sender: 141.163.170.165
bwctl: exec_line: iperf3 -c 194.36.11.37 -B 141.163.170.165 -f m -p 5656 -V -Z
--omit 4 -t 10
bwctl: run_tool: tester: iperf3
bwctl: run_tool: receiver: 194.36.11.37
bwctl: run_tool: sender: 141.163.170.165
bwctl: start_tool: 3673076540.078318
iperf 3.1.2
Linux localhost.localdomain 2.6.32-573.26.1.el6.x86_64 #1 SMP Wed May 4
00:57:44 UTC 2016 x86_64
Time: Tue, 24 May 2016 11:02:20 GMT
Connecting to host 194.36.11.37, port 5656
     Cookie: localhost.localdomain.1464087740.079
     TCP MSS: 1368 (default)
[ 15] local 141.163.170.165 port 47616 connected to 194.36.11.37 port 5656
Starting Test: protocol: TCP, 1 streams, 131072 byte blocks, omitting 4
seconds, 10 second test
[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[ 15]   0.00-1.00   sec  11.0 MBytes  92.4 Mbits/sec    2   1.62 MBytes
(omitted)
[ 15]   1.00-2.00   sec  0.00 Bytes  0.00 Mbits/sec    1   1.62 MBytes
(omitted)
[ 15]   2.00-3.00   sec  0.00 Bytes  0.00 Mbits/sec    0   1.62 MBytes
(omitted)
[ 15]   3.00-4.00   sec  0.00 Bytes  0.00 Mbits/sec    1   1.62 MBytes
(omitted)
[ 15]   0.00-1.00   sec  0.00 Bytes  0.00 Mbits/sec    0   1.62 MBytes
[ 15]   1.00-2.00   sec  0.00 Bytes  0.00 Mbits/sec    0   1.62 MBytes
[ 15]   2.00-3.00   sec  0.00 Bytes  0.00 Mbits/sec    0   1.62 MBytes
[ 15]   3.00-4.00   sec  0.00 Bytes  0.00 Mbits/sec    1   1.62 MBytes
[ 15]   4.00-5.00   sec  0.00 Bytes  0.00 Mbits/sec    0   1.62 MBytes
[ 15]   5.00-6.00   sec  0.00 Bytes  0.00 Mbits/sec    0   1.62 MBytes
[ 15]   6.00-7.00   sec  0.00 Bytes  0.00 Mbits/sec    0   1.62 MBytes
[ 15]   7.00-8.00   sec  0.00 Bytes  0.00 Mbits/sec    0   1.62 MBytes
[ 15]   8.00-9.00   sec  0.00 Bytes  0.00 Mbits/sec    0   1.62 MBytes
[ 15]   9.00-10.00  sec  0.00 Bytes  0.00 Mbits/sec    0   1.62 MBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
Test Complete. Summary Results:
[ ID] Interval           Transfer     Bandwidth       Retr
[ 15]   0.00-10.00  sec  0.00 Bytes  0.00 Mbits/sec    1             sender
[ 15]   0.00-10.00  sec  0.00 Bytes  0.00 Mbits/sec                  receiver
CPU Utilization: local/sender 0.2% (0.1%u/0.2%s), remote/receiver 0.1%
(0.0%u/0.2%s)

iperf Done.
bwctl: stop_tool: 3673076554.301276
bwctl: stop_endpoint: 3673076554.301276

SENDER END

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