Are you using RAWAPI? I have data only for that mode. Chances are you need to speed up your Ethernet driver and choose a faster checksum algorithm or write or find one in assembly language. Both make a huge difference.
I have clocked lwIP at 940MbS (megabits average - 960 peak) using a tcp_sent callback but doing nothing in the callback. When I use the data as our application needs it (copying it into sequential memory), I could get 500-600MbS using a DMA memory copy, but this would lock up the PowerPC intermittently. Using a high-speed memory copy (in assembly language) we can run our application with 300-400MbS - this includes an interrupt running at 36kHz consuming almost half of the processor bandwidth. We are sending 1 to 2MB blasts from the PC as many as 7 or 8 per second. One critical point is that we must call tcp_output after a tcp_write for the PC to respond quickly. Our application has 99% of the data coming from the PC, not going to it. Be warned that WireShark affects the bandwidth at higher speeds. If you're not using the RAWAPI, this won't help you too much except to show you what we found lwIP to be capable of achieving. Bill From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Gary Olson Sent: Tuesday, September 30, 2008 11:00 AM To: [email protected] Subject: [lwip-users] LWIP Delay between Consecutive Packets Hi, I am trying to figure out if I can increase my TCP bandwidth. Using a PC timer I see that as I send TCP Packets that the delay is in the range of 500 us on average. There may be a couple at the start with much less delay between TCP Packets. But most of the packets after the first few are in the same range. Does any one know what the LWIP Delayed Acknowledge timer is set to. I have been looking on the web in general for a solution to this. I program my PC in Visual C++ using Winsock so I am going to see if using TCP NO DELAY will have a positive change. Since this will cause the Nagle Algorithm to be disabled and packets are supposed to be sent immediately rather waiting for a delayed acknowledge to come first. Thank You, Gary Kudos! Thanks!
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