What is the actual maximum speed of Jetson AGX Xavier PCIE Ethernet?
                                    
                                    Mar 04, 2024
                                
                            Dear Nvidia Team
We are using PCIe to communicate between two Xaviers, According to << Jetson AGX Xavier PCIe Endpoint Mode>>, but have some doubts in actual use.
Version information about the systems we use: JetPack4.6   kernel version:4.9.253-tegra   Device:Jetson AGX Xavier
The tests I have performed are as follows:
1.Xavier B starts iperf3 server
# iperf3 -s
-----------------------------------------------------------
Server listening on 5201
-----------------------------------------------------------
Accepted connection from 192.168.66.6, port 40890
[  5] local 192.168.66.7 port 5201 connected to 192.168.66.6 port 40892
[ ID] Interval           Transfer     Bandwidth
[  5]   0.00-1.00   sec   359 MBytes  3.01 Gbits/sec
[  5]   1.00-2.00   sec   478 MBytes  4.01 Gbits/sec
[  5]   2.00-3.00   sec   423 MBytes  3.55 Gbits/sec
[  5]   3.00-4.00   sec   464 MBytes  3.89 Gbits/sec
[  5]   4.00-5.00   sec   484 MBytes  4.06 Gbits/sec
[  5]   5.00-6.00   sec   553 MBytes  4.64 Gbits/sec
[  5]   6.00-7.00   sec   551 MBytes  4.63 Gbits/sec
[  5]   7.00-8.00   sec   521 MBytes  4.37 Gbits/sec
[  5]   8.00-9.00   sec   167 MBytes  1.40 Gbits/sec
[  5]   9.00-10.00  sec   172 MBytes  1.44 Gbits/sec
[  5]  10.00-11.00  sec   168 MBytes  1.41 Gbits/sec
[  5]  11.00-12.00  sec   172 MBytes  1.44 Gbits/sec
[  5]  12.00-13.00  sec   161 MBytes  1.35 Gbits/sec
[  5]  13.00-14.00  sec   358 MBytes  3.01 Gbits/sec
[  5]  14.00-14.16  sec  90.2 MBytes  4.63 Gbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth
[  5]   0.00-14.16  sec  0.00 Bytes  0.00 bits/sec                  sender
[  5]   0.00-14.16  sec  5.00 GBytes  3.03 Gbits/sec                  receiver
2.Xavier A starts iperf3 client,5G data volume test using 10000M bandwidth
# iperf3 -c 192.168.66.7 -b 10000M -n 5G
Connecting to host 192.168.66.7, port 5201
[  4] local 192.168.66.6 port 40892 connected to 192.168.66.7 port 5201
[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[  4]   0.00-1.00   sec   379 MBytes  3.18 Gbits/sec    0   1.11 MBytes
[  4]   1.00-2.00   sec   472 MBytes  3.95 Gbits/sec    0   1.11 MBytes
[  4]   2.00-3.00   sec   431 MBytes  3.62 Gbits/sec    0   1.11 MBytes
[  4]   3.00-4.00   sec   464 MBytes  3.89 Gbits/sec    0   1.11 MBytes
[  4]   4.00-5.00   sec   483 MBytes  4.06 Gbits/sec    0   1.11 MBytes
[  4]   5.00-6.00   sec   554 MBytes  4.64 Gbits/sec    0   1.54 MBytes
[  4]   6.00-7.00   sec   551 MBytes  4.62 Gbits/sec    0   1.54 MBytes
[  4]   7.00-8.00   sec   507 MBytes  4.25 Gbits/sec    0   3.93 MBytes
[  4]   8.00-9.00   sec   169 MBytes  1.42 Gbits/sec    0   3.93 MBytes
[  4]   9.00-10.00  sec   171 MBytes  1.43 Gbits/sec    0   3.93 MBytes
[  4]  10.00-11.00  sec   167 MBytes  1.40 Gbits/sec    0   3.93 MBytes
[  4]  11.00-12.00  sec   173 MBytes  1.45 Gbits/sec    0   3.93 MBytes
[  4]  12.00-13.00  sec   160 MBytes  1.35 Gbits/sec    0   3.93 MBytes
[  4]  13.00-14.00  sec   371 MBytes  3.12 Gbits/sec    0   3.93 MBytes
[  4]  14.00-14.12  sec  68.1 MBytes  4.63 Gbits/sec    0   3.93 MBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-14.12  sec  5.00 GBytes  3.04 Gbits/sec    0             sender
[  4]   0.00-14.12  sec  5.00 GBytes  3.04 Gbits/sec                  receiver
3.View the actual physical rate of the system PCIE
# lspci
0000:00:00.0 PCI bridge: NVIDIA Corporation Device 1ad0 (rev a1)
0000:01:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd Device a809
0005:00:00.0 PCI bridge: NVIDIA Corporation Device 1ad0 (rev a1)
0005:01:00.0 Network controller: NVIDIA Corporation Device 2296
root@neolix-xavier-rt:/home/nvidia#   318  lspci -n | grep -i 0005:01:00.0
# lspci -n | grep -i 0005:01:00.0
0005:01:00.0 0280: 10de:2296
# lspci -n | grep -i 0005:01:00.0
0005:01:00.0 0280: 10de:2296
root@neolix-xavier-rt:/home/nvidia# lspci -n -d 10de:2296 -vvv | grep --color Width
                LnkCap: Port #0, Speed 16GT/s, Width x8, ASPM not supported, Exit Latency L0s <1us, L1 <64us
                LnkSta: Speed 16GT/s, Width x8, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
After carrying out the above tests, it was found that there are several problems in use:
- Using lspci, we can see that the actual PCIE rate is 16GT/s, Width x8, and the throughput is about 15.754GB/s, which is 126Gb/s, but the performance measurement using iperf3 shows that the average rate is only about 3.04 Gbits/sec, which is similar to The actual physical PCIE rate is very different, why is this?
 - From the test results of iperf3, it can be seen that the rate of pcie ethernet fluctuates between 1.35 Gbits/sec and 4.64 Gbits/sec. The results of many long-term tests are also the same. What is the reason for the unstable rate?
 - What is the maximum actual speed of the official Jetson AGX Xavier using PCIE Ethernet?
 
Thank you for your support.
Best regards