Thanks, that document is very helpful. I set up TCP Blaster as a client, not a server, just because it was easier for me to send data from Linux with netcat. I'll try it as a server, I just have to look up the right netcat params.
I am glad to hear from you that's your experience was that NuttX is limited by the network. That's great! :) I do think high speed transfers should be possible using Ethernet over USB and I would love to get it working at close to the link speed of 480Mbps. That would really help for the application I'm building. Right now I'm trying to get the ethernet to work on the SAMA5D36-Xplained board. NuttX compiles, but the ethernet interfaces won't go up. I am using ETH0 with the GMAC and ETH1 with EMACA. I've set the PHYs as laid out in the README.txt. Not sure how to debug, but I am looking for how ifconfig tries to get the interface to come up... On Sun, Jan 12, 2020 at 11:28 AM Gregory Nutt <spudan...@gmail.com> wrote: > > > Ok, thanks. I did do that yesterday with tcpdump while trying to find the > > closing-early problem with the header lengths. Now with the header length > > calculation things look good– at low speeds, the packet exchange matches > > what I am getting from a Linux web server. No retransmissions, resets, or > > missed ACKs. I will try a high-speed capture and examine it. > > > > I did try tcpblaster last night, and can only get about 100 KB/s maximum > – > > about 800kbps, so much less than the 480Mbps that's possible. So that is > > probably part of the constraint. The SAMA5D36 has USB DMA.so it should be > > possible to get 100Mbps or higher... I will try with the Gigabit Ethernet > > and see if I can find the bottleneck. > > This might be useful to you: > https://cwiki.apache.org/confluence/display/NUTTX/TCP+Network+Performance > > TCP blaster can be set up for sending to or receiving from the device. > Which are you doing? > > I have verified NuttX TCP Tx performance with tcpblaster and found that > it runs at about the maximum for the network I was using (I was using a > slow, half duplex network). You are probably not being limited by the > USB transfer rate, but by the network transfer rate. Well both should > have and effect, but the (probably) network transfer rate at 100Mbit/sec > is a lot lower than the USB transfer rate. > > 100KB/s is 800Kbit/sec which is considerably lower than the network > transfer rate. > > Rx performance is more difficult to characterize. > > > > > -- Adam Feuer <a...@starcat.io>
