TCP Read Optimization #74

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1. SajjadPourali

   assigned

   Copilot

   on Oct 15, 2025
2. SajjadPourali commented on Oct 15, 2025

   

   SajjadPourali

   on Oct 15, 2025

   Collaborator

   More actions

   Do you mean this part?

   ipstack/src/stream/tcb.rs

   Lines 54 to 55 in 92e5a87

   	inflight_packets: BTreeMap<SeqNum, InflightPacket>,
   	unordered_packets: BTreeMap<SeqNum, Vec<u8>>,
3. SajjadPourali

   unassigned

   Copilot

   on Oct 15, 2025
4. Orvaxis commented on Oct 19, 2025

   

   Orvaxis

   on Oct 19, 2025

   Last edited by Orvaxis

   ContributorAuthor

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   Here, every time a new data packet is received, it is sent through the channel, which frees up the receive window. However, the data in the channel might not be consumed in time by the upstream TCP Stream, causing it to accumulate here.

   ipstack/src/stream/tcp.rs

   Lines 846 to 853 in 92e5a87

   	if let Some(data) = tcb.consume_unordered_packets(8192) {
   	let hint = if state == TcpState::Established { "normally" } else { "still" };
   	log::trace!("{network_tuple} {state:?}: {l_info} {hint} receiving data, len = {}", data.len());
   	data_tx.send(data).map_err(|e| std::io::Error::new(BrokenPipe, e))?;
   	read_notify.lock().unwrap().take().map(|w| w.wake_by_ref()).unwrap_or(());
   	write_packet_to_device(up_packet_sender, network_tuple, tcb, None, ACK, None, None)?;
   	}
   	Ok(())

   Recently, I discovered a similar issue here, which causes traffic to accumulate in bursts during high-throughput uploads.

   ipstack/src/lib.rs

   Lines 13 to 15 in 92e5a87

   	pub(crate) type PacketSender = UnboundedSender<NetworkPacket>;
   	pub(crate) type PacketReceiver = UnboundedReceiver<NetworkPacket>;
   	pub(crate) type SessionCollection = AHashMap<NetworkTuple, PacketSender>;

   ipstack/src/lib.rs

   Lines 177 to 181 in 92e5a87

   	match sessions.entry(network_tuple) {
   	std::collections::hash_map::Entry::Occupied(entry) => {
   	let len = packet.payload.as_ref().map(|p| p.len()).unwrap_or(0);
   	log::trace!("packet sent to stream: {network_tuple} len {len}");
   	entry.get().send(packet).map_err(std::io::Error::other)?;