How does linkerd read/write data?

[fz197]

Hi, I'm just started playing with Linkerd. From the Flamegraph I generated from perf, I can only see writev system call but no read/readv. How does Linkerd proxy read data from the socket? (A pointer to the source code will be will helpful!).

Thanks in advance!

[olix0r]

For TCP forwarding, most of that will go through linkerd_duplex::HalfDuplex::poll_buffer (which calls into tokio_util::io::poll_read_buf, and so on).

For HTTP proxying, most of that will be managed by hyper and h2. I'd have to do a little digging to nail down the exact read calls there, but they'll boil down to a AsyncRead::poll_read on tokio::net::TcpStream.

[fz197]

great, thanks a lot!