feature request: support for MSG_ZEROCOPY and MSG_TRUNC flags

[bltierney]

See discussion 1520, and see neper for sample code. https://github.com/google/neper

This will be a little bit of work, as you'll need to use send/recv instead of read/write calls.

Discussed in https://github.com/esnet/iperf/discussions/1520

^{Originally posted by rjmcmahon May 17, 2023} Hi,

I'm considering adding 200G+ support to iperf 2 and thought it might be interesting to get iperf 3 engineers' thoughts. One initial question I have is about using sendfile vs the SO_ZEROCOPY/MSG_ZEROCOPY socket/send option. Any thoughts on that?

Also, I'm wondering about BIG TCP and if there have been any experiments with v6 or possibly v4?

Bob

PS. A reddit thread on 400G

[davidBar-On]

Submitted PR #1690 with support for the requested features (see the PR for details).

[davidBar-On]

Enhanced functionality for this issue now implemented by PRs #1717 (SKIP-RX-COPY) and and #1720 (zerocopy using MSG_ZEROCOPY/SO_ZEROCOPY). PR #1690 with the initial suggestions for the implementations is now closed.