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← Local optimizations of easily measured code metrics do not produce…
17 connected korrents · 12 moments on record from 29 Aug 2003 to 7 Sept 2026.
Everything filed under software quality
software quality
Everything filed under software performance
software performance
Everything filed under coding agents
coding agents
Everything filed under formal proof
formal proof Same subject Same subject Same subject Same subject Same subject Same subject Same subject Same subject Same subject Same subject Same subject Same subject Same subject Same subject Same subject Same subject Same subject Read this korrent: Local optimizations of easily measured code metrics do not produce global optimums, and matter less the fewer people look at the output. Local optimizations of easily measured code metrics do not produce global optimums, and matter less the fewer people look at the output. Last stated 4 days ago
7 Sept 2026
AR
Armin Ronacher — holds since 2026-09-07 — tap for who they are
Same subject: "Optimize it later" would be safe advice only if every engineer already knew how to avoid the architectural mistakes that no later optimization can remove. — tap to centre the map on it "Optimize it later" would be safe advice only if every engineer already knew how to avoid the architectural mistakes that no later optimization can remove. Last stated 2 weeks ago
26 Aug 2026
CM
Casey Muratori — holds since 2026-08-26 — tap for who they are
Same subject: Lines of code cannot measure productivity, because better-designed code is shorter. — tap to centre the map on it Lines of code cannot measure productivity, because better-designed code is shorter. Last stated 23 years ago
29 Aug 2003
MF
Martin Fowler — holds since 2003-08-29 — tap for who they are
Same subject: Optimization means measuring the gap between your code and what the hardware could theoretically do, not making changes and checking whether the statistics improved. — tap to centre the map on it Optimization means measuring the gap between your code and what the hardware could theoretically do, not making changes and checking whether the statistics improved. Last stated 2 weeks ago
26 Aug 2026
CM
Casey Muratori — holds since 2026-08-26 — tap for who they are
Same subject: Optimising a single metric is a trap, because the second-order consequences of the change only surface much later. — tap to centre the map on it Optimising a single metric is a trap, because the second-order consequences of the change only surface much later. Last stated 3 months ago
9 Jun 2026
BG
Bill Gurley — holds since 2026-06-09 — tap for who they are
Same subject: Locality is what makes a language good for AI: if a single file states what it imports and what it offers, a model never has to hold the whole program at once. — tap to centre the map on it Locality is what makes a language good for AI: if a single file states what it imports and what it offers, a model never has to hold the whole program at once. Last stated 4 months ago
13 May 2026
AH
Anders Hejlsberg — holds since 2026-05-13 — tap for who they are
Same subject: Hand-optimizing hot spots barely matters any more, because the libraries are already fast and CPUs are extremely good at running bad code quickly; what is left is architecture. — tap to centre the map on it Hand-optimizing hot spots barely matters any more, because the libraries are already fast and CPUs are extremely good at running bad code quickly; what is left is architecture. Last stated 2 weeks ago
26 Aug 2026
CM
Casey Muratori — holds since 2026-08-26 — tap for who they are
Same subject: Code and files generated by tools are pollution: hand-writing them is worth the effort because the bloat slows everything down for everyone. — tap to centre the map on it Code and files generated by tools are pollution: hand-writing them is worth the effort because the bloat slows everything down for everyone. Last stated 7 years ago
15 Oct 2019
DS
Derek Sivers — holds since 2019-10-15 — tap for who they are
Same subject: Everyone on a team who makes architectural decisions must understand performance, because a codebase that can be optimized later only ends up that way on purpose. — tap to centre the map on it Everyone on a team who makes architectural decisions must understand performance, because a codebase that can be optimized later only ends up that way on purpose. Last stated 2 weeks ago
26 Aug 2026
CM
Casey Muratori — holds since 2026-08-26 — tap for who they are
Same subject: A language-agnostic conformance suite is the most powerful thing you can hand a coding agent, because the whole instruction becomes: write code until these tests pass. — tap to centre the map on it A language-agnostic conformance suite is the most powerful thing you can hand a coding agent, because the whole instruction becomes: write code until these tests pass. Last stated 6 months ago
19 Mar 2026
SW
Simon Willison — holds since 2026-03-19 — tap for who they are
Same subject: A passing test suite is not evidence that the software works, so an agent must also be made to start the thing and exercise it the way a person would. — tap to centre the map on it A passing test suite is not evidence that the software works, so an agent must also be made to start the thing and exercise it the way a person would. Last stated 6 months ago
19 Mar 2026
SW
Simon Willison — holds since 2026-03-19 — tap for who they are
Same subject: A team that slows down and reads every pull request and every line of code should expect only a 30 to 50 percent productivity lift from AI. — tap to centre the map on it A team that slows down and reads every pull request and every line of code should expect only a 30 to 50 percent productivity lift from AI. Last stated 2 months ago
15 Jul 2026
DH
Dex Horthy — holds since 2026-07-15 — tap for who they are
Same subject: A test checks a handful of examples; a proof settles an infinite state space, which is why formal methods can say things testing never can. — tap to centre the map on it A test checks a handful of examples; a proof settles an infinite state space, which is why formal methods can say things testing never can. Last stated 5 months ago
22 Apr 2026
MK
Martin Kleppmann — holds since 2026-04-22 — tap for who they are
Same subject: Formal methods are a niche tool; property-based testing is the one most engineers should adopt, and stopping there is a fine place to stop. — tap to centre the map on it Formal methods are a niche tool; property-based testing is the one most engineers should adopt, and stopping there is a fine place to stop. Last stated a month ago
29 Jul 2026
HW
Hillel Wayne — holds since 2026-07-29 — tap for who they are
Same subject: AI is making formal methods more popular without making them mainstream, moving them from about a tenth of a per cent of engineers to three tenths. — tap to centre the map on it AI is making formal methods more popular without making them mainstream, moving them from about a tenth of a per cent of engineers to three tenths. Last stated a month ago
29 Jul 2026
HW
Hillel Wayne — holds since 2026-07-29 — tap for who they are
Same subject: Agent-written code that runs and passes its tests is not enough: security, maintainability and being able to roll it back still need humans in the loop. — tap to centre the map on it Agent-written code that runs and passes its tests is not enough: security, maintainability and being able to roll it back still need humans in the loop. Last stated 3 months ago
7 Jun 2026
TF
Tony Fadell — holds since 2026-06-07 — tap for who they are
Same subject: Having an AI agent write tests costs tokens in the short run and saves them in the long run, because the classic failure is that the code does not work. — tap to centre the map on it Having an AI agent write tests costs tokens in the short run and saves them in the long run, because the classic failure is that the code does not work. Last stated 2 months ago
1 Jul 2026
KB
Kent Beck — holds since 2026-07-01 — tap for who they are
Same subject: Keeping a codebase clean now pays off directly rather than aesthetically, because a coding agent will copy the patterns already in it almost exactly. — tap to centre the map on it Keeping a codebase clean now pays off directly rather than aesthetically, because a coding agent will copy the patterns already in it almost exactly. Last stated 6 months ago
19 Mar 2026
SW
Simon Willison — holds since 2026-03-19 — tap for who they are
At the centre
Local optimizations of easily measured code metrics do not produce global optimums, and matter less the fewer people look at the output.
Holds Read this korrent →
"Optimize it later" would be safe advice only if every engineer already knew how to avoid the architectural mistakes that no later optimization can remove.
Holds CM Casey Muratori
Lines of code cannot measure productivity, because better-designed code is shorter.
Holds MF Martin Fowler
Optimization means measuring the gap between your code and what the hardware could theoretically do, not making changes and checking whether the statistics improved.
Holds CM Casey Muratori
Optimising a single metric is a trap, because the second-order consequences of the change only surface much later.
Holds BG Bill Gurley
Locality is what makes a language good for AI: if a single file states what it imports and what it offers, a model never has to hold the whole program at once.
Holds AH Anders Hejlsberg
Hand-optimizing hot spots barely matters any more, because the libraries are already fast and CPUs are extremely good at running bad code quickly; what is left is architecture.
Holds CM Casey Muratori
Code and files generated by tools are pollution: hand-writing them is worth the effort because the bloat slows everything down for everyone.
Holds
Everyone on a team who makes architectural decisions must understand performance, because a codebase that can be optimized later only ends up that way on purpose.
Holds CM Casey Muratori
A language-agnostic conformance suite is the most powerful thing you can hand a coding agent, because the whole instruction becomes: write code until these tests pass.
Holds
A passing test suite is not evidence that the software works, so an agent must also be made to start the thing and exercise it the way a person would.
Holds
A team that slows down and reads every pull request and every line of code should expect only a 30 to 50 percent productivity lift from AI.
Holds DH Dex Horthy
A test checks a handful of examples; a proof settles an infinite state space, which is why formal methods can say things testing never can.
Holds MK Martin Kleppmann
Formal methods are a niche tool; property-based testing is the one most engineers should adopt, and stopping there is a fine place to stop.
Holds HW Hillel Wayne
AI is making formal methods more popular without making them mainstream, moving them from about a tenth of a per cent of engineers to three tenths.
Holds HW Hillel Wayne
Agent-written code that runs and passes its tests is not enough: security, maintainability and being able to roll it back still need humans in the loop.
Holds TF Tony Fadell
Having an AI agent write tests costs tokens in the short run and saves them in the long run, because the classic failure is that the code does not work.
Holds KB Kent Beck
Keeping a codebase clean now pays off directly rather than aesthetically, because a coding agent will copy the patterns already in it almost exactly.
Holds