Comment by Jenda_

3 years ago

I don't know Golang, but how does the function in git-lfs that writes to the socket look like? Is it writing in 50-byte chunks? Why?

Because I guess even with TCP_NODELAY, if I submit reasonably huge chunks of data (e.g. 4K, 64K...) to the socket, they will get split into reasonably-sized packets.

1 comment

Jenda_

microtherion 3 years ago

The code in question seems to be this portion of SendMessageWithData in ssh/protocol.go [1]:

  buf := make([]byte, 32768)
  for {
    n, err := data.Read(buf)
    if n > 0 {
      err := conn.pl.WritePacket(buf[0:n])
      if err != nil {
        return err
      }
    }
    if err != nil {
      break
    }
  }

The write packet size seems to be determined by how much data the reader returns at a time. That could backfire if the reader were e.g. something like line at a time (no idea if something like that exists in Golang), but that does not seem to be the case here.

[1] https://github.com/git-lfs/git-lfs/blob/d3716c9024083a45771c...