Top all-time · #3269
Speculative Branches
Personal blog · specbranch.comprogrammingsystemshardware
Speculative Branches is a personal blog at specbranch.com about programming, systems and hardware. Since 2022, 23 different Hacker News readers have linked it 42 times, most often “The Knight Capital Disaster: losing 440M in 45 minutes (2023)”. No feed was found, so read it on the site itself.
Too few sampled comments (8) to say how often HN recommends it.?
Why HN links it
HN readers cite its posts on lookup tables versus computation, running on one big server, the Knight Capital trading failure, and generating perfectly distributed random floats, usually as background for their own points.
Summarised by Claude from a sample of 8 HN comments that link here. Each comment is marked recommending, critical or neutral (citing without judging); how this works.
Thoughts on software, hardware, performance, math, and similar topics
Most-linked posts?
- The Knight Capital Disaster: losing 440M in 45 minutes (2023)4 people · 5 mentions · first linked 2023-11-28
- Use one big server4 people · 4 mentions · first linked 2022-08-02
- You (Probably) Shouldn't Use a Lookup Table4 people · 4 mentions · first linked 2022-05-05
- Rest in Peace, Optane3 people · 3 mentions · first linked 2022-09-23
- Division of 8bit nums in C is faster than a DIV instruction on Intel Haswell CPU2 people · 3 mentions · first linked 2022-02-24
- Perfect Random Floating-Point Numbers2 people · 2 mentions · first linked 2025-05-04
- Python Is Like Assembly2 people · 2 mentions · first linked 2022-07-06
- The Most Useful Statistical Test You've Never Heard Of2 people · 2 mentions · first linked 2022-07-05
- Abstraction Is Expensive2 people · 2 mentions · first linked 2022-12-07
- Time Programming for Lawyers and Jurors2 people · 2 mentions · first linked 2024-07-12
What Hacker News says?
Reminds me of https://www.specbranch.com/posts/one-big-server/
Comment linking /posts/one-big-server/
on “AWS to bare metal two years later: Answering your questions about leaving AWS”Submitted Use one big server as a story · 1413 points
HN discussionI'm not the person you responded to, but I think the gist of it is: what it is is not defined by how it is used. Python, at its core, is a scripting language, like awk and bash. The other uses don't change that. Occasionally, a technology breaks out of its intended domain. Python is one of these - it plays host to lots of webservers, and even a filesystem (dropbox). Similarly, HTML is a text markup language, but tha…
Comment linking /posts/python-and-asm/
on “Python 3.11 vs 3.10 performance”Submitted Use One Big Server (2022) as a story · 350 points
HN discussionShamelessly plugging my own blog post on this: https://specbranch.com/posts/knight-capital/ The TL;DR of Knight is that Knight had several things go wrong at the same time, and had no circuit breaker for the problem that did not stop trading for the whole firm for the day. Most trading firms have had things go badly, but the holes in the Swiss cheese aligned for Knight (and they were larger than many other firms). T…
Comment linking /posts/knight-capital/
on “CrowdStrike ex-employees: 'Quality control was not part of our process'”Submitted Teach your kids bridge, not poker as a story · 327 points
HN discussionIf that is faster would seem to depend on if you can get most lookups from the L2 cache. Otherwise you're waiting for main memory, which is a few hundred cycles. Even with multiple loads in parallel, it would be hard to beat arithmetic. https://specbranch.com/posts/lookup-tables/
Comment linking /posts/lookup-tables/
on “The One Billion Row Challenge in Go: from 1m45s to 4s in nine solutions”Submitted Perfect Random Floating-Point Numbers as a story · 115 points
HN discussionWhy you (probably) shouldn't use a lookup table https://specbranch.com/posts/lookup-tables/ gives some discussion about when it's appropriate generally. My narrow experience is that you can do a lot of real time calculation before it's faster to do a lookup.
Comment linking /posts/lookup-tables/
on “New exponent functions that make SiLU and SoftMax 2x faster, at full accuracy”Submitted You (Probably) Shouldn't Use a Lookup Table as a story · 8 points
HN discussionIt's not unlimited scale, it was just over 700_000 people according to https://news.ycombinator.com/item?id=32320697 . If your web page is 100 kilobytes, which seems like the maximum that would be reasonable, that's 70 gigabytes of traffic. AWS charges US$0.09 per GB so this is US$7. If you eliminate the cloud premium it's closer to US$1. In fact loading their home page takes 3.1 MB for me over two minutes. Searchin…
Comment linking /posts/one-big-server/
on “FlightRadar24 crashes due to surge in users tracking SPAR19”Submitted The Knight Capital Disaster: losing 440M in 45 minutes (2023) as a story · 7 points
HN discussionYes, that is a good clarification - it uses wider precision internally, but it takes floating point restrictions and operations into account. If you otherwise used Remez, you would have to just quantize the coefficients blindly and then tweak (probably manually) if something was off. Shamelessly plugging, you can sort of see the old-school process here (using integers and mixed-precision fixed point is harder with S…
Comment linking /posts/faster-div8/
on “How does a computer/calculator compute logarithms?”Submitted Rest in Peace, Optane as a story · 6 points
HN discussionThe powerpeg feature flag had been deprecated for 9 years? In aggregate, yes, the engineering led to the disaster, but the specific engineers had been making everyone piles of money for a long time. The mistakes were fatal, but in a tiny amount of time on a system that old it's honestly surprising it didn't happen sooner. https://specbranch.com/posts/knight-capital/
Comment linking /posts/knight-capital/
on “Software development in the time of strange new angels”Submitted Abstraction Is Expensive as a story · 5 points
HN discussionI am running a set of SBCs, but I read that it is better to use one server [1]. I suppose one could go with a VM, or portainer, or Yacht, or some other software to visualize everything. Right now I am using a set or solutions: * email * [2] * files * using NextCloud * blog * using Hugo * news * using my own RSS reader * pihole * to filter things What I consider to use in the future * pictures * using photoprism * ci…
Comment linking /posts/one-big-server/
on “I Am Leaving”Submitted What Happened with FPGA Acceleration? as a story · 4 points
HN discussionI have my own crazy solution to the division problem: https://www.specbranch.com/posts/faster-div8/ This is actually faster than DIV on old architectures, but there are lots of reasons why you shouldn't use it (code cache pollution and pipeline congestion). I have been working on combining my initial 8-bit precision guess with a few rounds of Goldschmidt division to compete with 64-bit DIV, but I am currently not qu…
Comment linking /posts/faster-div8/
on “Algos in Plain English – Efficient Division Without Mult, Div, or Mod Operators”Submitted Rest in Peace, Optane (2022) as a story · 3 points
HN discussionThis article shows how to generate perfectly-distributed random floats: https://specbranch.com/posts/fp-rand/
Comment linking /posts/fp-rand/
on “Show HN: Fast Random Library for C++17”Submitted The Most Useful Statistical Test You've Never Heard Of as a story · 3 points
HN discussionIndeed, I'd rather have the program crash rather than repeat this nightmare: https://specbranch.com/posts/knight-capital/
Comment linking /posts/knight-capital/
on “Rob Pike: Gobs of data (2011)”Submitted Performance Numbers Worth Knowing as a story · 3 points
HN discussionI kind of fell off the wagon after a strong 2022, but there are a few good ones: https://specbranch.com
Comment linking /
on “Ask HN: Could you share your personal blog here?”Submitted Solving Fibonacci-like problems in constant time as a story · 3 points
HN discussionSubmitted Less-Than-Linear Fibonacci as a story · 3 points
HN discussionSubmitted Abstraction Is Expensive (2022) as a story · 2 points
HN discussionSubmitted A Cryptographically Secret Santa as a story · 2 points
HN discussionSubmitted Five Nine Problems as a story · 2 points
HN discussion
