Dan Luu: there's no reason for software to be slow anymore — LLMs democratize perf work

tokenbender · x · 2026-08-24

Dan Luu argues "there's no reason for software to be slow anymore": performance work that used to require a rare, specialized team has dropped in cost by orders of magnitude — anyone who can type a few sentences can now do it, making optimizations worthwhile for projects far beyond the largest or most lucrative ones.

Key points:

Marc Brooker agrees and adds: dynamic custom software fitted to a particular workload (not a class of workloads) is a likely outcome, reminiscent of FFTW and old demoscene tricks (e.g., re-using code as textures for cache locality);
Against the meme that "code was never the hard part, so AI doesn't help," Michael Malis counters: in domains like JIT compilers, writing the code absolutely was the hard part — their rarity shows implementation was historically too expensive.

tokenbender shares it with the takeaway: don't use LLM-saved time to produce more mediocre work; produce better, performant code instead.

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Dan Luu: there's no reason for software to be slow anymore — LLMs democratize perf work

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