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ChibiHash: Small, Fast 64 bit hash function

(nrk.neocities.org)
104 points thunderbong | 2 comments | 18 Nov 24 00:23 UTC | HN request time: 0s | source
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palsecam ◴[18 Nov 24 10:52 UTC] No.42171316[source]▶
See also: “Meow hash” by the legendary Casey Muratori, a fast non-cryptographic hash function: https://github.com/cmuratori/meow_hash

> It’s the fastest hash function we know of, and we have benchmarked all the ones we could find. On modern Intel x64 CPUs, it hashes 16 bytes per cycle single-threaded. This means in cache it can hash at a rate of 64 gigabytes per second on a 4.2gHz machine. Out of cache, it hashes at whatever speed your main memory bus can provide to a single core, since that is usually the limiting factor on modern x64 CPUs.

> It has also now been tuned to be the fastest hash on small inputs, too. Despite the fact that it is a full 128-bit hash, it still outperforms “fast” 64-bit hashes across all input sizes.

— https://archive.is/CQOVm (originally https://mollyrocket.com/meowhash)

Discussion on HN: https://news.ycombinator.com/item?id=29038813 & https://news.ycombinator.com/item?id=18262627

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1. zamalek ◴[18 Nov 24 14:56 UTC] No.42172847[source]▶
From the archive link (blog post published 2018):

> To our surprise, we found a lack of published, well-optimized, large-data hash functions.

Murmur was released in 2008. Murmur3 in 2011. Release dates on higher quality functions are not easy to find, but I am sure that there were more around.

This type of thing is why I take Casey's claims with a huge dose of salt.

replies(1): >>42183415 #
2. Sesse__ ◴[19 Nov 24 13:51 UTC] No.42183415[source]▶
> This type of thing is why I take Casey's claims with a huge dose of salt.

My impression in general is that Casey is a fairly decent engineer who has somehow been elevated into godhood by a subset of users.