I would like to have UDP packets copied directly from the ethernet adapter into my userspace buffer
Some details on my setup:
I am receiving data from a pair of gigabit ethernet cameras. Combined I am receiving 28800 UDP packets per second (1 packet per line * 30FPS * 2 cameras * 480 lines). There is no way for me to switch to jumbo frames, and I am already looking into tuning driver level interrupts for reduc开发者_开发技巧ed CPU utilization. What I am after here is reducing the number of times I am copying this ~40MB/s data stream.
This is the best source I have found on this, but I was hoping there was a more complete reference or proof that such an approach worked out in practice.
This article may be useful:
http://yusufonlinux.blogspot.com/2010/11/data-link-access-and-zero-copy.html
Your best avenues are recvmmsg
and increasing RX interrupt coalescing.
http://lwn.net/Articles/334532/
You can move lower and match how Wireshark/tcpdump operate but it becomes futile to attempt any serious processing above it having to decode everything yourself.
At only 30,000 packets per second I wouldn't worry too much about copying packets, those problems arise when dealing with 3,000,000 messages per second.
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