Hi Bob,
this getting weird from my understanding. Increasing the window not
increasing the total datagram send to the receiver.
ubuntu@vm1:~$ iperf3 -b 1000m -c 192.168.0.212 -l 1402 -O 5 -t 15 -R -V -u
-w 100k
iperf 3.7
Linux vm1 4.15.0-112-generic #113-Ubuntu SMP Thu Jul 9 23:41:39 UTC 2020
x86_64
Control connection MSS 1390
warning: UDP block size 1402 exceeds TCP MSS 1390, may result in
fragmentation / drops
Time: Mon, 03 Aug 2020 06:56:09 GMT
Connecting to host 192.168.0.212, port 5201
Reverse mode, remote host 192.168.0.212 is sending
Cookie: ihfjcorkrnzqrpwzvus4kaca5kxu7trpyexa
Target Bitrate: 1000000000
[ 5] local 192.168.0.104 port 40981 connected to 192.168.0.212 port 5201
Starting Test: protocol: UDP, 1 streams, 1402 byte blocks, omitting 5
seconds, 15 second test, tos 0
[ ID] Interval Transfer Bitrate Jitter Lost/Total
Datagrams
[ 5] 0.00-1.00 sec 14.3 MBytes 120 Mbits/sec 0.045 ms 322/11016
(2.9%) (omitted)
[ 5] 1.00-2.00 sec 14.3 MBytes 120 Mbits/sec 0.042 ms 58/10735
(0.54%) (omitted)
[ 5] 2.00-3.00 sec 13.7 MBytes 115 Mbits/sec 0.053 ms 106/10327
(1%) (omitted)
[ 5] 3.00-4.00 sec 14.5 MBytes 122 Mbits/sec 0.056 ms 61/10937
(0.56%) (omitted)
[ 5] 4.00-5.00 sec 14.2 MBytes 119 Mbits/sec 0.040 ms 540/11191
(4.8%) (omitted)
[ 5] 0.00-1.00 sec 13.9 MBytes 116 Mbits/sec 0.040 ms 0/10411 (0%)
[ 5] 1.00-2.00 sec 13.3 MBytes 112 Mbits/sec 0.044 ms 537/10500
(5.1%)
[ 5] 2.00-3.00 sec 13.9 MBytes 117 Mbits/sec 0.042 ms 0/10391 (0%)
[ 5] 3.00-4.00 sec 13.9 MBytes 117 Mbits/sec 0.057 ms 338/10758
(3.1%)
[ 5] 4.00-5.00 sec 14.1 MBytes 118 Mbits/sec 0.045 ms 132/10653
(1.2%)
[ 5] 5.00-6.00 sec 14.4 MBytes 121 Mbits/sec 0.047 ms 61/10837
(0.56%)
[ 5] 6.00-7.00 sec 14.8 MBytes 124 Mbits/sec 0.046 ms 91/11186
(0.81%)
[ 5] 7.00-8.00 sec 14.7 MBytes 123 Mbits/sec 0.037 ms 80/11054
(0.72%)
[ 5] 8.00-9.00 sec 14.4 MBytes 120 Mbits/sec 0.034 ms 0/10734
(0%)
[ 5] 9.00-10.00 sec 13.5 MBytes 114 Mbits/sec 0.037 ms 661/10783
(6.1%)
[ 5] 10.00-11.00 sec 13.7 MBytes 115 Mbits/sec 0.045 ms 36/10297
(0.35%)
[ 5] 11.00-12.00 sec 13.5 MBytes 113 Mbits/sec 0.028 ms 0/10079
(0%)
[ 5] 12.00-13.00 sec 13.5 MBytes 113 Mbits/sec 0.049 ms 146/10243
(1.4%)
[ 5] 13.00-14.00 sec 14.7 MBytes 123 Mbits/sec 0.045 ms 0/10965
(0%)
[ 5] 14.00-15.00 sec 14.1 MBytes 118 Mbits/sec 0.111 ms 0/10531
(0%)
- - - - - - - - - - - - - - - - - - - - - - - - -
Test Complete. Summary Results:
[ ID] Interval Transfer Bitrate Jitter Lost/Total
Datagrams
[ 5] 0.00-15.05 sec 214 MBytes 119 Mbits/sec 0.000 ms 0/159431
(0%) sender
[ 5] 0.00-15.00 sec 210 MBytes 118 Mbits/sec 0.111 ms 2082/159421
(1.3%) receiver
iperf Done.
ubuntu@vm1:~$ iperf3 -b 1000m -c 192.168.0.212 -l 1402 -O 5 -t 15 -R -V -u
-w 400k
iperf 3.7
Linux vm1 4.15.0-112-generic #113-Ubuntu SMP Thu Jul 9 23:41:39 UTC 2020
x86_64
Control connection MSS 1390
warning: UDP block size 1402 exceeds TCP MSS 1390, may result in
fragmentation / drops
Time: Mon, 03 Aug 2020 06:54:51 GMT
Connecting to host 192.168.0.212, port 5201
Reverse mode, remote host 192.168.0.212 is sending
Cookie: cngqxagnbyc6epxx2qpas22gw4wanwybinkd
Target Bitrate: 1000000000
[ 5] local 192.168.0.104 port 38205 connected to 192.168.0.212 port 5201
Starting Test: protocol: UDP, 1 streams, 1402 byte blocks, omitting 5
seconds, 15 second test, tos 0
[ ID] Interval Transfer Bitrate Jitter Lost/Total
Datagrams
[ 5] 0.00-1.00 sec 14.4 MBytes 121 Mbits/sec 0.072 ms 284/11077
(2.6%) (omitted)
[ 5] 1.00-2.00 sec 15.6 MBytes 131 Mbits/sec 0.080 ms 208/11872
(1.8%) (omitted)
[ 5] 2.00-3.00 sec 15.8 MBytes 132 Mbits/sec 0.050 ms 58/11866
(0.49%) (omitted)
[ 5] 3.00-4.00 sec 14.1 MBytes 118 Mbits/sec 0.042 ms 95/10649
(0.89%) (omitted)
[ 5] 4.00-5.00 sec 13.8 MBytes 115 Mbits/sec 0.040 ms 0/10285
(0%) (omitted)
[ 5] 0.00-1.00 sec 14.4 MBytes 120 Mbits/sec 0.035 ms 62/10798
(0.57%)
[ 5] 1.00-2.00 sec 13.7 MBytes 115 Mbits/sec 0.043 ms 445/10717
(4.2%)
[ 5] 2.00-3.00 sec 14.2 MBytes 120 Mbits/sec 0.037 ms 0/10657 (0%)
[ 5] 3.00-4.00 sec 14.5 MBytes 121 Mbits/sec 0.040 ms 0/10808 (0%)
[ 5] 4.00-5.00 sec 14.7 MBytes 123 Mbits/sec 0.036 ms 0/10961 (0%)
[ 5] 5.00-6.00 sec 13.9 MBytes 117 Mbits/sec 0.040 ms 0/10432 (0%)
[ 5] 6.00-7.00 sec 14.5 MBytes 122 Mbits/sec 0.049 ms 0/10835 (0%)
[ 5] 7.00-8.00 sec 14.7 MBytes 123 Mbits/sec 0.040 ms 0/10964 (0%)
[ 5] 8.00-9.00 sec 14.4 MBytes 121 Mbits/sec 0.043 ms 0/10781 (0%)
[ 5] 9.00-10.00 sec 14.2 MBytes 119 Mbits/sec 0.058 ms 63/10650
(0.59%)
[ 5] 10.00-11.00 sec 11.6 MBytes 97.7 Mbits/sec 0.026 ms 0/8712 (0%)
[ 5] 11.00-12.00 sec 14.5 MBytes 121 Mbits/sec 0.033 ms 204/11015
(1.9%)
[ 5] 12.00-13.00 sec 14.5 MBytes 122 Mbits/sec 0.050 ms 0/10868 (0%)
[ 5] 13.00-14.00 sec 13.2 MBytes 111 Mbits/sec 0.041 ms 120/9980
(1.2%)
[ 5] 14.00-15.00 sec 14.1 MBytes 119 Mbits/sec 0.040 ms 316/10857
(2.9%)
- - - - - - - - - - - - - - - - - - - - - - - - -
Test Complete. Summary Results:
[ ID] Interval Transfer Bitrate Jitter Lost/Total
Datagrams
[ 5] 0.00-15.04 sec 213 MBytes 119 Mbits/sec 0.000 ms 0/159045
(0%) sender
[ 5] 0.00-15.00 sec 211 MBytes 118 Mbits/sec 0.040 ms 1210/159034
(0.76%) receiver
iperf Done.
ubuntu@vm1:~$ iperf3 -b 1000m -c 192.168.0.212 -l 1402 -O 5 -t 15 -R -V -u
iperf 3.7
Linux vm1 4.15.0-112-generic #113-Ubuntu SMP Thu Jul 9 23:41:39 UTC 2020
x86_64
Control connection MSS 1390
warning: UDP block size 1402 exceeds TCP MSS 1390, may result in
fragmentation / drops
Time: Mon, 03 Aug 2020 06:59:20 GMT
Connecting to host 192.168.0.212, port 5201
Reverse mode, remote host 192.168.0.212 is sending
Cookie: l6sisiehpqorqyxcg45732upghijmtrduja7
Target Bitrate: 1000000000
[ 5] local 192.168.0.104 port 33996 connected to 192.168.0.212 port 5201
Starting Test: protocol: UDP, 1 streams, 1402 byte blocks, omitting 5
seconds, 15 second test, tos 0
[ ID] Interval Transfer Bitrate Jitter Lost/Total
Datagrams
[ 5] 0.00-1.00 sec 15.0 MBytes 126 Mbits/sec 0.038 ms 109/11319
(0.96%) (omitted)
[ 5] 1.00-2.00 sec 14.6 MBytes 122 Mbits/sec 0.041 ms 210/11102
(1.9%) (omitted)
[ 5] 2.00-3.00 sec 13.3 MBytes 112 Mbits/sec 0.043 ms 0/9945 (0%)
(omitted)
[ 5] 3.00-4.00 sec 13.7 MBytes 115 Mbits/sec 0.029 ms 64/10345
(0.62%) (omitted)
[ 5] 4.00-5.00 sec 14.3 MBytes 120 Mbits/sec 0.043 ms 0/10670
(0%) (omitted)
[ 5] 0.00-1.00 sec 13.5 MBytes 113 Mbits/sec 0.067 ms 0/10065
(0%)
[ 5] 1.00-2.00 sec 12.1 MBytes 101 Mbits/sec 0.054 ms 0/9048 (0%)
[ 5] 2.00-3.00 sec 13.3 MBytes 112 Mbits/sec 0.037 ms 47/10004
(0.47%)
[ 5] 3.00-4.00 sec 13.8 MBytes 116 Mbits/sec 0.049 ms 139/10463
(1.3%)
[ 5] 4.00-5.00 sec 13.1 MBytes 110 Mbits/sec 0.047 ms 0/9787 (0%)
[ 5] 5.00-6.00 sec 14.6 MBytes 122 Mbits/sec 0.040 ms 0/10889
(0%)
[ 5] 6.00-7.00 sec 14.2 MBytes 119 Mbits/sec 0.043 ms 34/10684
(0.32%)
[ 5] 7.00-8.00 sec 14.7 MBytes 123 Mbits/sec 0.054 ms 31/11006
(0.28%)
[ 5] 8.00-9.00 sec 14.3 MBytes 120 Mbits/sec 0.058 ms 0/10701
(0%)
[ 5] 9.00-10.00 sec 14.2 MBytes 119 Mbits/sec 0.036 ms 205/10857
(1.9%)
[ 5] 10.00-11.00 sec 14.1 MBytes 118 Mbits/sec 0.044 ms 234/10765
(2.2%)
[ 5] 11.00-12.00 sec 13.9 MBytes 117 Mbits/sec 0.049 ms 32/10450
(0.31%)
[ 5] 12.00-13.00 sec 14.3 MBytes 120 Mbits/sec 0.038 ms 0/10687
(0%)
[ 5] 13.00-14.00 sec 13.7 MBytes 115 Mbits/sec 0.031 ms 29/10302
(0.28%)
[ 5] 14.00-15.00 sec 14.6 MBytes 123 Mbits/sec 0.034 ms 152/11052
(1.4%)
- - - - - - - - - - - - - - - - - - - - - - - - -
Test Complete. Summary Results:
[ ID] Interval Transfer Bitrate Jitter Lost/Total
Datagrams
[ 5] 0.00-15.04 sec 210 MBytes 117 Mbits/sec 0.000 ms 0/156771
(0%) sender
[ 5] 0.00-15.00 sec 208 MBytes 117 Mbits/sec 0.034 ms 903/156759
(0.58%) receiver
I set the bitrate to 1Gbps.
ubuntu@vm1:~$ sudo cat /proc/sys/net/ipv4/udp_rmem_min
4096
ubuntu@vm1:~$ sudo cat /proc/sys/net/ipv4/udp_mem
91704 122274 183408
ubuntu@vm1:~$ sudo cat /proc/sys/net/ipv4/tcp_rmem
4096 131072 6291456
Best Regards,
Zufar Dhiyaulhaq
On Mon, Aug 3, 2020 at 9:14 AM Bob McMahon <[email protected]> wrote:
> Not at an intermediate network but at the host computer (or VM) that is
> transmitting
>
> Bob
>
> On Sun, Aug 2, 2020 at 6:49 PM Zufar Dhiyaulhaq <[email protected]>
> wrote:
>
>> Hi Bob and Tim,
>>
>> Thank you for responding to my question. sometime today will try
>> increasing the window. Since I am testing this in a virtual environment
>> (OpenStack), it is hard to define the wire limitation. I get UDP throughput
>> somewhere between 100-120 Mbps and TCP throughput between 50-100 Mbps
>> (using 1402 (GENEVE) & 1410 (VXLAN) mss since I am using tunneling
>> protocol).
>>
>> In the case of UDP that Bob saying. so the limitation you said is in the
>> intermediate network, right? so the client will force to send all packet
>> (by increasing window size) but will get dropped in the intermediate net?
>>
>> Best Regards,
>> Zufar Dhiyaulhaq
>>
>>
>> On Mon, Aug 3, 2020 at 2:05 AM Bob McMahon <[email protected]>
>> wrote:
>>
>>> If the bottleneck is the transmitter's wire that means things will back
>>> up behind that. The network stack on the client will queue packets. Since
>>> it's in a state of oversubscription there is no way for the client to ever
>>> drain the bottleneck so-to-speak. A bottleneck is when the service time is
>>> less than the arrival time. So one host to look more closely at the client
>>> host, where the bottleneck is, to understand. There are two things
>>> happening, iperf is issuing writes() and the network stack is sending
>>> packets. While related, they're different.
>>>
>>> The iperf client issues a write() to cause the sending of a packet. If
>>> the operating system has system buffers it will accept the write()
>>> otherwise it has two choices, block or suspend the write until a system
>>> buffer comes available or error on the write. What I suspect you're seeing
>>> is an os blocking on the write(). Increasing the window size will allow
>>> the os to accept the write and pass the packet to the network stack, which
>>> will in turn drop the packet. Then you'll see packet loss.
>>>
>>> Did you try with a bigger window?
>>>
>>> Bob
>>>
>>> On Fri, Jul 31, 2020 at 4:29 PM Zufar Dhiyaulhaq <
>>> [email protected]> wrote:
>>>
>>>> Hi Bob,
>>>>
>>>> Thanks for replying. In my understanding, when increasing the bitrate
>>>> above the bandwidth/throughput, it will increase the packet loss right? but
>>>> in my case, I increase to 9 Gbps and still not seeing any packet loss. Did
>>>> increasing window size will increasing packet loss? and why that can
>>>> happen?
>>>>
>>>> I am trying to simulate packet loss.
>>>>
>>>> Thanks
>>>>
>>>> Best Regards,
>>>> Zufar Dhiyaulhaq
>>>>
>>>>
>>>> On Sat, Aug 1, 2020 at 5:28 AM Bob McMahon <[email protected]>
>>>> wrote:
>>>>
>>>>> Try to increase the window size with -w on the client. This will
>>>>> allow the operating system to accept the write and drop packets within the
>>>>> stack. If the window is too small the operating system will block the
>>>>> write until os buffers are available.
>>>>>
>>>>> Bob
>>>>>
>>>>> On Fri, Jul 31, 2020 at 8:56 AM Zufar Dhiyaulhaq <
>>>>> [email protected]> wrote:
>>>>>
>>>>>> Hi Folks,
>>>>>>
>>>>>> I have a problem with iperf3, I try to simulate packet loss with
>>>>>> Iperf3 with increasing the bitrate above the bandwidth. But packet loss
>>>>>> output not increasing.
>>>>>>
>>>>>> Ubuntu 18.04
>>>>>> Iperf 3.7.3
>>>>>>
>>>>>> I don't know why this is happening? Is there any bug with Iperf? this
>>>>>> sounds stupid for me.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> *ubuntu@vm1:~$ iperf3 -c 192.168.0.92 --udp -t 20 --bitrate 9000m -R
>>>>>> -Viperf 3.7Linux vm1 4.15.0-112-generic #113-Ubuntu SMP Thu Jul 9
>>>>>> 23:41:39
>>>>>> UTC 2020 x86_64Control connection MSS 1390Setting UDP block size to
>>>>>> 1390Time: Fri, 31 Jul 2020 15:53:39 GMTConnecting to host 192.168.0.92,
>>>>>> port 5201Reverse mode, remote host 192.168.0.92 is sending Cookie:
>>>>>> geu5ktrvwtalkelbszen5ym4rzxfp5xgzwdy Target Bitrate: 9000000000[ 5]
>>>>>> local 192.168.0.226 port 47999 connected to 192.168.0.92 port
>>>>>> 5201Starting
>>>>>> Test: protocol: UDP, 1 streams, 1390 byte blocks, omitting 0 seconds, 20
>>>>>> second test, tos 0[ ID] Interval Transfer Bitrate
>>>>>> Jitter Lost/Total Datagrams[ 5] 0.00-1.00 sec 13.8 MBytes 116
>>>>>> Mbits/sec 0.081 ms 269/10704 (2.5%) [ 5] 1.00-2.00 sec 13.7
>>>>>> MBytes
>>>>>> 115 Mbits/sec 0.085 ms 0/10346 (0%) [ 5] 2.00-3.00 sec 13.6
>>>>>> MBytes 114 Mbits/sec 0.035 ms 126/10365 (1.2%) [ 5] 3.00-4.00
>>>>>> sec
>>>>>> 12.8 MBytes 107 Mbits/sec 0.033 ms 279/9946 (2.8%) [ 5]
>>>>>> 4.00-5.00
>>>>>> sec 13.5 MBytes 113 Mbits/sec 0.051 ms 262/10427 (2.5%) [ 5]
>>>>>> 5.00-6.00 sec 13.2 MBytes 111 Mbits/sec 0.058 ms 0/9965 (0%) [
>>>>>> 5]
>>>>>> 6.00-7.00 sec 13.3 MBytes 111 Mbits/sec 0.044 ms 32/10047
>>>>>> (0.32%)
>>>>>> [ 5] 7.00-8.00 sec 13.0 MBytes 109 Mbits/sec 0.053 ms 43/9874
>>>>>> (0.44%) [ 5] 8.00-9.00 sec 13.0 MBytes 109 Mbits/sec 0.042 ms
>>>>>> 34/9847 (0.35%) [ 5] 9.00-10.00 sec 13.6 MBytes 114 Mbits/sec
>>>>>> 0.055 ms 78/10305 (0.76%) [ 5] 10.00-11.00 sec 13.5 MBytes 113
>>>>>> Mbits/sec 0.070 ms 0/10171 (0%) [ 5] 11.00-12.00 sec 13.1 MBytes
>>>>>> 110 Mbits/sec 0.047 ms 0/9851 (0%) [ 5] 12.00-13.00 sec 13.3
>>>>>> MBytes
>>>>>> 112 Mbits/sec 0.034 ms 0/10055 (0%) [ 5] 13.00-14.00 sec 13.4
>>>>>> MBytes 112 Mbits/sec 0.040 ms 36/10136 (0.36%) [ 5] 14.00-15.00
>>>>>> sec
>>>>>> 13.9 MBytes 117 Mbits/sec 0.055 ms 437/10921 (4%) [ 5]
>>>>>> 15.00-16.00
>>>>>> sec 13.2 MBytes 111 Mbits/sec 0.043 ms 25/9964 (0.25%) [ 5]
>>>>>> 16.00-17.00 sec 13.2 MBytes 110 Mbits/sec 0.043 ms 21/9942 (0.21%)
>>>>>> [ 5] 17.00-18.00 sec 12.9 MBytes 108 Mbits/sec 0.046 ms 0/9702
>>>>>> (0%) [ 5] 18.00-19.00 sec 13.4 MBytes 112 Mbits/sec 0.050 ms
>>>>>> 208/10294 (2%) [ 5] 19.00-20.00 sec 13.5 MBytes 113 Mbits/sec
>>>>>> 0.048 ms 0/10152 (0%) - - - - - - - - - - - - - - - - - - - - - - - -
>>>>>> -Test Complete. Summary Results:[ ID] Interval Transfer
>>>>>> Bitrate Jitter Lost/Total Datagrams[ 5] 0.00-20.04 sec
>>>>>> 269
>>>>>> MBytes 113 Mbits/sec 0.000 ms 0/203058 (0%) sender[ 5] 0.00-20.00
>>>>>> sec 267 MBytes 112 Mbits/sec 0.048 ms 1850/203014 (0.91%)
>>>>>> receiver*
>>>>>>
>>>>>> Thank you
>>>>>>
>>>>>> Best Regards,
>>>>>> Zufar Dhiyaulhaq
>>>>>> _______________________________________________
>>>>>> Iperf-users mailing list
>>>>>> [email protected]
>>>>>> https://lists.sourceforge.net/lists/listinfo/iperf-users
>>>>>>
>>>>>
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