Hi all,
I'm new here, actually I'm a HW engineer and not very experienced with networking. To perform the other experiment I need to evaluate my ethernet TPT to see if it gating my DUT's capability.
When I did the TPT test with iperf, there is something odd...
- If I use the default setting of UDP, the TPT is always around 29mbps. Even I enlarge -b to 1000m. It always TX 25~29mbps from client. My commands is iperf -c 192.168.1.150 -u -b1000m -w 2m -i1
------------------------------------------------------------
Client connecting to 192.168.1.150, UDP port 5001
Sending 1470 byte datagrams
UDP buffer size: 2.00 MByte
------------------------------------------------------------
[1912] local 192.168.1.99 port 1250 connected with 192.168.1.150 port 5001
[ ID] Interval Transfer Bandwidth
[1912] 0.0- 1.0 sec 2.92 MBytes 24.5 Mbits/sec
[1912] 1.0- 2.0 sec 3.33 MBytes 27.9 Mbits/sec
[1912] 2.0- 3.0 sec 3.18 MBytes 26.6 Mbits/sec
[1912] 3.0- 4.0 sec 3.25 MBytes 27.3 Mbits/sec
[1912] 4.0- 5.0 sec 3.20 MBytes 26.8 Mbits/sec
- If I use TCP, the TPT can reach 400m~500mbps. My commands is iperf -c 192.168.1.150 -w2m -i1
------------------------------------------------------------
Client connecting to 192.168.1.150, TCP port 5001
TCP window size: 2.00 MByte
------------------------------------------------------------
[1912] local 192.168.1.99 port 1252 connected with 192.168.1.150 port 5001
[ ID] Interval Transfer Bandwidth
[1912] 0.0- 1.0 sec 48.2 MBytes 404 Mbits/sec
[1912] 1.0- 2.0 sec 52.4 MBytes 439 Mbits/sec
[1912] 2.0- 3.0 sec 55.9 MBytes 469 Mbits/sec
[1912] 3.0- 4.0 sec 61.3 MBytes 514 Mbits/sec
[1912] 4.0- 5.0 sec 54.5 MBytes 457 Mbits/sec
- If I add in -l to 60000 then the UDP TPT can reach 500mbps, but limited on 500mbps. My commands is iperf -c 192.168.1.99 -u -b 1000m -w 2m -i 1 -l 60000.
------------------------------------------------------------
Client connecting to 192.168.1.150, UDP port 5001
Sending 60000 byte datagrams
UDP buffer size: 2.00 MByte
------------------------------------------------------------
[1912] local 192.168.1.99 port 1254 connected with 192.168.1.150 port 5001
[ ID] Interval Transfer Bandwidth
[1912] 0.0- 1.0 sec 57.2 MBytes 480 Mbits/sec
[1912] 1.0- 2.0 sec 59.6 MBytes 500 Mbits/sec
[1912] 2.0- 3.0 sec 61.4 MBytes 515 Mbits/sec
[1912] 3.0- 4.0 sec 61.4 MBytes 515 Mbits/sec
[1912] 4.0- 5.0 sec 59.7 MBytes 501 Mbits/sec
- I also try variable -l number from 10000~60000 the data transmitted from client will change accordingly.
-l 10000 --> 160 Mbits/sec
-l 50000 --> 504 Mbits/sec
Even the TPT >500m is enough to my experiment requirement, but I'm still wondering is it safe to use the bigger number of -l? As the description said it's default value is 1460.
Could anyone possibly to answer me:
Whats is the exactly meaning of the -l parameter (Iperf_length), I know it's the buffer to write or read. But not very clear to me the buffer is for what and why do we need buffer?
I also compare it with other windows machines, they needn't use this way to get the TPT higher than 25~29mbps. Is there any modification my NB (or OS) needing?
My environment:
OS: Windows XP SP3 version 2002
Ethernet: Realtek PCIe GBE Family Controller
Driver version: 5.774.1026.2010
Thanks in advance
Kircheis
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