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demerphq
smhasher
C++2017–2018
demerphq / smhasher

smhasher

Discover this repository through its Hacker News conversations.

Testing & Quality
Explore on GitHubRead Hacker News discussions
2Distinct people
3Mentions
0Explicit recommenders
79GitHub stars
REPOSITORY AT A GLANCE

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What it is

A public description has not been verified.

Where it is used

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What people are saying

No recommendation phrase was found in the indexed comments.

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Also in these discussions

Mentioned in the same Hacker News threads. That is not proof they are substitutes.

This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 5:04:57 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by month3 dated mentions

Observed mentions: 2017-03-25 07:38:49 UTC to 2018-08-14 14:12:25 UTC.

0122017-03-01 00:00:00 UTC to 2017-04-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 commentsMar 20172017-04-01 00:00:00 UTC to 2017-05-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2017-05-01 00:00:00 UTC to 2017-06-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2017-06-01 00:00:00 UTC to 2017-07-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2017-07-01 00:00:00 UTC to 2017-08-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2017-08-01 00:00:00 UTC to 2017-09-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2017-09-01 00:00:00 UTC to 2017-10-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2017-10-01 00:00:00 UTC to 2017-11-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2017-11-01 00:00:00 UTC to 2017-12-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 commentsNov 20172017-12-01 00:00:00 UTC to 2018-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2018-01-01 00:00:00 UTC to 2018-02-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2018-02-01 00:00:00 UTC to 2018-03-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2018-03-01 00:00:00 UTC to 2018-04-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2018-04-01 00:00:00 UTC to 2018-05-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2018-05-01 00:00:00 UTC to 2018-06-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2018-06-01 00:00:00 UTC to 2018-07-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2018-07-01 00:00:00 UTC to 2018-08-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2018-08-01 00:00:00 UTC to 2018-09-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 commentsAug 2018

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
Mar 20172017-03-01 00:00:00 UTC2017-04-01 00:00:00 UTC202
Apr 20172017-04-01 00:00:00 UTC2017-05-01 00:00:00 UTC000
May 20172017-05-01 00:00:00 UTC2017-06-01 00:00:00 UTC000
Jun 20172017-06-01 00:00:00 UTC2017-07-01 00:00:00 UTC000
Jul 20172017-07-01 00:00:00 UTC2017-08-01 00:00:00 UTC000
Aug 20172017-08-01 00:00:00 UTC2017-09-01 00:00:00 UTC000
Sep 20172017-09-01 00:00:00 UTC2017-10-01 00:00:00 UTC000
Oct 20172017-10-01 00:00:00 UTC2017-11-01 00:00:00 UTC000
Nov 20172017-11-01 00:00:00 UTC2017-12-01 00:00:00 UTC000
Dec 20172017-12-01 00:00:00 UTC2018-01-01 00:00:00 UTC000
Jan 20182018-01-01 00:00:00 UTC2018-02-01 00:00:00 UTC000
Feb 20182018-02-01 00:00:00 UTC2018-03-01 00:00:00 UTC000
Mar 20182018-03-01 00:00:00 UTC2018-04-01 00:00:00 UTC000
Apr 20182018-04-01 00:00:00 UTC2018-05-01 00:00:00 UTC000
May 20182018-05-01 00:00:00 UTC2018-06-01 00:00:00 UTC000
Jun 20182018-06-01 00:00:00 UTC2018-07-01 00:00:00 UTC000
Jul 20182018-07-01 00:00:00 UTC2018-08-01 00:00:00 UTC000
Aug 20182018-08-01 00:00:00 UTC2018-09-01 00:00:00 UTC101

What Hacker News says

3 sources
erthink·Aug 14, 2018
t1ha aka "Fast Positive Hash" - In most cases up to 15% faster than StadtX, xxHash, mum-hash, Metro-hash, etc. Simple benchmark is included (git close && make). The quality and speed could be checked by Reini Urban's (https://github.com/rurban/smhasher) and Yves Orton's (https://github.com/demerphq/smhasher) forks of SMHasher suite. Reasonable to note: t1ha have two injection points of each data word inside the loop of entropy sponge.
In T1ha: even more Faster and Better hash functions family
demerphq·Mar 26, 2017
It is only small in older hashes. Modern hashes tend to have a state larger than both the seed and the input block. See: https://github.com/demerphq/smhasher/blob/master/HashAnatomy... It actually turns out there are performance benefit by having a larger seed, but not too large. (If you think about it this makes sense consider how many bits you can change with an average combining operation, and with a worse case combining operation.)
In Brief Introduction To General Purpose Hash Functions
demerphq·Mar 25, 2017
You are welcome. I wanted add another point. rurban does have a bit of a point. The hash functions you referenced in your article are generally old and low quality, and slow. FNV is neither a good hash, nor is it fast. FNV_yt is very fast, but not the best quality hash function, it fails many tests in SMHasher, including some I personally consider dealbreaker: failing avalanche tests is unacceptable. Both rurban and I have (independently) spent considerable time testing about 100 hash functions using the hash test suite smhasher. In addition I have greatly enhanced smhasher, and included test results and graphs in my version. Included in my fork is the --stream option so you can test different hash functions in counter mode with tools like the dieharder RNG test suite. https://github.com/demerphq/smhasher https://github.com/rurban/smhashe
Read the rest
r These are the FNV test results from my version of SMHasher: FNV1a 32 32 32 FAILED 99 of 183 tests. Avalanche: 17-41, Crc-MultiCollision: 81, 83, 85-86, 88-91, 94, 96-98, 100, Cyclic: 42-52, Hi-Lo: 157-158, HiBit-Null: 150-152, Highbits2: 147-149, Highbits: 144-146, LowBit-Null: 153-155, Lowbits: 142-143, Murmur2-MultiCollision: 101-110, Murmur3A-MultiCollision: 111, 113, 117, 119-120, Murmur3F-MultiCollision: 122-127, 129-130, OverAll: 183, Text: 160-165, TwoBytes: 54-56, 63, Zeroes: 167-168 FNV1a_YT 32 32 32 FAILED 67 of 181 tests. Avalanche: 15-39, Differential: 9-14, Hi-Lo: 154-156, HiBit-Null: 148-150, Highbits2: 145-147, Highbits: 142-144, Lowbits: 139-141, OverAll: 181, Sparse: 74-78, Text: 157-158, 160-163, TwoBytes: 51, 53-61 FNV64 64 64 64 FAILED 66 of 183 tests. Avalanche: 17-41, Cyclic: 43-45, 47, 49, 51-52, Hi-Lo: 157-158, HiBit-Null: 151-152, Highbits2: 148-149, Highbits: 145-146, LowBit-Null: 154-155, Lowbits: 142-143, OverAll: 183, Sparse: 65-67, 69, 71, 73, 75, 77, 79-80, Text: 160-162, 164-165, TwoBytes: 54-56, 58, 60, 62-63, Words: 182, Zeroes: 167-168 You can see text view of the full list at: https://github.com/demerphq/smhasher/blob/master/doc/summary... Also after reading this thread I added some graphs comparing performance of other hashes, including some that I have developed using genetic algorithm for use in Perl. Some of those hashes have hash-time performance at the top of the envelope (StadtX is very fast). https://github.com/demerphq/smhasher/blob/master/doc/graph/F... https://github.com/demerphq/smhasher/blob/master/doc/graph/F... https://github.com/demerphq/smhasher/blob/master/doc/graph/F... https://github.com/demerphq/smhasher/blob/master/doc/graph/F... You may also be interested in looking at https://github.com/demerphq/smhasher/blob/master/HashAnatomy... Good luck!
In Brief Introduction To General Purpose Hash Functions

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