IdeaWell

Project ideas from Hacker News discussions.

It's Always TCP_NODELAY

Original Article

Hacker News Discussion

📝 Discussion Summary (Click to expand)

1. Nagle's Algorithm Causes Unnecessary Latency in Modern Networks

Users widely recommend disabling it via TCP_NODELAY=1 for games, SSH, RPCs, and chatty protocols, as bandwidth savings are negligible compared to delays.

  • "Dumping the Nagle algorithm (by setting TCP_NODELAY) almost always makes sense and should be enabled by default." – anonymousiam
  • "Disabling Nagle's algorithm should be done as a matter of principle, there's simply no modern network configuration where it's beneficial." – armitron

2. Legacy Hardware and Unmaintained Apps Justify Keeping It as Default

Discussions highlight industrial, medical, and old devices (e.g., 10Mbps Ethernet, PLCs) that benefit from batching to avoid overwhelming shared networks.

  • "Everyone is forgetting the no delay is per application and not a system configuration. Yep, old things will still be old and that’s ok." – BikiniPrince
  • "If you worked in an industrial setting, legacy tech abounds due to the capital costs of replacing the equipment it supports." – hylaride

3. Interaction with Delayed ACKs Is the Core Problem

Nagle + delayed ACKs create 40-500ms stalls; fixes include disabling one/both or app-level buffering.

  • "You never want TCP_NODELAY off at the sending end, and delayed ACKs on at the receiving end." – Animats
  • "The core issue with Nagle’s algorithm (TCP_NODELAY off) is its interaction with TCP Delayed ACK." – drfignewton

🚀 Project Ideas

TCP Nagle Diagnostic Tool

Summary

  • A CLI tool that analyzes tcpdump/wireshark captures or live traffic to detect Nagle's algorithm delays, delayed ACK interactions, and recommends fixes like TCP_NODELAY or TCP_QUICKACK.
  • Core value: Quickly identifies "mystery latency" in games, SSH, DICOM, or RPCs without deep expertise.

Details

Key Value
Target Audience Developers debugging networking in games, servers, medical apps (e.g., eieio, miduil, TZubiri)
Core Feature Packet trace analysis with visualizations of buffering delays, RTT stats, and auto-suggestions
Tech Stack Go/Rust + libpcap + tshark integration + eBPF for live tracing
Difficulty Medium
Monetization Hobby

Notes

  • "I found this article while debugging some networking delays for a game" (eieio); HN users love tcpdump tools for instant insights.
  • High utility for HN crowd sharing traces; sparks discussions on edge cases like legacy hardware.

Legacy TCP Proxy (NoDelay Injector)

Summary

  • Transparent user-space proxy (LD_PRELOAD or iptables redirect) that forces TCP_NODELAY, TCP_QUICKACK, and optimal buffers on legacy apps/devices without source access.
  • Core value: Fixes clogs from old CT scanners, PLCs, DICOM servers on modern LANs instantly.

Details

Key Value
Target Audience Sysadmins/ops in hospitals, manufacturing, industrial IoT (e.g., TZubiri, electroly, hylaride)
Core Feature Intercept sockets, apply socketopts transparently, log delays; supports SSH/HPN-SSH passthrough
Tech Stack C/Rust with eBPF/XDP for kernel bypass + DPDK for high perf
Difficulty High
Monetization Revenue-ready: Freemium (open core + enterprise support)

Notes

  • "I wonder how this fix could be implemented without source code access. Suppose an old ct scanner is clogging up the network" (TZubiri); builds on libnodelay mentions.
  • Practical for legacy-heavy envs; HN would debate deployment in prod DCs.

MessageFlush TCP Library

Summary

  • Cross-platform library providing a message-oriented TCP API with auto-TCP_NODELAY, user-space buffering, explicit flush(), and vectored I/O for low-latency apps.
  • Core value: Fixes stream API pains (no flush, tiny writes) for games, SSH, RPCs without reinventing framing.

Details

Key Value
Target Audience Game devs, backend devs building chatty protocols (e.g., eieio's SSH games, saghm's DB client)
Core Feature send_message(buf, flush_now), recv_message(); auto-batches small writes, cross-lang bindings
Tech Stack Rust/Go core + FFI for C/Python/JS; io_uring/WSASendMsg for perf
Difficulty Medium
Monetization Revenue-ready: Open source + paid hosted benchmarks/CDN

Notes

  • "the socket API does not (really) have a function to flush the buffers" (x2rj); "message oriented" desires (derriz, calineczka).
  • HN loves libs like this (e.g., QUIC wrappers); great for multiplayer/SSH experiments.

Read Later