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jsheardyesterday at 6:29 PM1 replyview on HN

Has anyone benchmarked 64bit memory on the current implementations? There's the potential for performance regressions there because they could exploit the larger address space of 64bit hosts to completely elide bounds checks when running 32bit WASM code, but that doesn't work if the WASM address space is also 64bit.


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kgyesterday at 6:33 PM

> WebAssembly apps tend to run slower in 64-bit mode than they do in 32-bit mode. This performance penalty depends on the workload, but it can range from just 10% to over 100%—a 2x slowdown just from changing your pointer size.

> This is not simply due to a lack of optimization. Instead, the performance of Memory64 is restricted by hardware, operating systems, and the design of WebAssembly itself.

https://spidermonkey.dev/blog/2025/01/15/is-memory64-actuall...

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