Recently I upgraded my AMD-based PC on a livestream, and I installed an Innodisk EGPL-T101 10 Gbps M.2 NIC (link to Innodisk product page).
Under Linux, I could get through 9.4 Gbps using iperf3 between the PC and my Mac Studio. But under Windows, I could only get up to about 4.5 Gbps (tested around 1h 27m into the stream)!
I recently had a server with some bandwidth limitations (tested using scp and rsync -P), where I was wondering if the problem was the data being transferred, or the server's link speed.
The simplest way to debug and verify TCP performance is to install iperf3 and run an iperf speed test between the server and my computer.
On the server, you run iperf3 -s, and on my computer, iperf3 -c [server ip].
But iperf3 requires port 5201 (by default) to be open on the server, and in many cases—especially if the server is inside a restricted environment and only accessible through SSH (e.g. through a bastion or limited to SSH connectivity only)—you won't be able to get that port accessible.
So in my case, I wanted to run iperf through an SSH tunnel. This isn't ideal, because you're testing the TCP performance through an encrypted connection. But in this case both the server and my computer are extremely new/fast, so I'm not too worried about the overhead lost to the connection encryption, and my main goal was to get a performance baseline.
Since the Raspberry Pi Compute Module 4 was introduced last year, I've been testing a variety of PCI Express NICs with it. One of the main types of NIC I'm interested in is cheap 2.5 Gigabit Ethernet adapters.
2.5 Gigabits is about the highest reasonable bandwidth you can get through the PCI Express Gen 2.0 x1 lane on the Raspberry Pi, and it's also a lot more accessible than 10 Gigabit networking, especially for home users who might already have Cat5e runs that they are loathe to swap out for Cat6 or better cabling.
In my testing, besides discovering that not all 10 Gbps SFP+ transceivers are created equal, I found out that when it comes to performance, the Linux driver you're using matters—a lot.
If you read the title of this blog post and are thinking, "10 Gbps on a Pi? You're nuts!," well, check out my video on using the ASUS XG-C100C 10G NIC on the Raspberry Pi CM4. Back? Good.
To be clear: it's impossible to route 10 gigabits of total network throughput through any Raspberry Pi on the market today.
But it is possible to connect to a 10 gigabit network at 10GBase-T speeds using a Raspberry Pi Compute Module 4 and an appropriate PCI Express 10G NIC. And on my Pi PCI Express site, I documented exactly how I got an ASUS XG-C100C working on the Raspberry Pi. All it takes is a quick recompile of the kernel, and away it goes!
I didn't know it at the time, but my results testing the EDUP WiFi 6 card (which uses the Intel AX200 chipset) on the Raspberry Pi in December weren't accurate.
It doesn't get 1.34 gigabits of bandwidth with the Raspberry Pi Compute Module 4 like I stated in my December video, WiFi 6 on the Raspberry Pi CM4 makes it Fly!.
I'm very thorough in my benchmarking, and if there's ever a weird anomaly, I try everything I can to prove or disprove the result before sharing it with anyone.
In this case, since I was chomping at the bit to move on to testing a Rosewill 2.5 gigabit Ethernet card, I didn't spend as much time as I should have re-verifying my results.
