Need card #131 · Relevance Medium · Status New

Performance Bottlenecks and Thread Support for NumPy in the Browser

Updated 9/22/2026, 22:03:31

Problem

When using NumPy in the browser, users encounter performance bottlenecks, particularly the lack of multi‑threading (pthreads) support that limits GEMM and other compute‑intensive tasks, and the need for extra COOP/COEP headers on static hosting platforms like GitHub Pages to use SharedArrayBuffer. Moreover, reliance on BLAS means performance gains often require waiting for a full NumPy release rather than immediate updates.

Pain points

Questions to verify

Evidence

quote · @Anonymous
The dynamic-linking detail is the part I find most interesting. On PyPI, NumPy wheels vendor a BLAS snapshot, so a BLAS improvement means waiting for the next NumPy release. Here OpenBLAS is its own conda package, so a JupyterLite / notebook.link environment picks up 0.3.35 by adding a channel and nothing else changes. That's a real payoff of treating wasm32 as a conda platform instead of a wheel target.
quote · @Anonymous
Wouldn't AI rewrite of these legacy Fortran packages like BLAS be easier at this point than trying to keep Fortran alive?

Disclaimer: this card is distilled by AI from community discussions as “pain point evidence”. It is a starting point for need analysis and validation, not a “validated market need”. AI has analytical limits; please open the original discussion above to manually verify before key decisions.