Re: [boost] Any interest in hashing algorithms SHA and/or FNV1a?

Subject: Re: [boost] Any interest in hashing algorithms SHA and/or FNV1a?
From: Niall Douglas (s_sourceforge_at_[hidden])
Date: 2013-11-13 12:11:20

On 12 Nov 2013 at 10:52, foster brereton wrote:

> Would these algorithms be of general use to the Boost community? If so
> I would be willing to submit them formally.

Be aware that AFIO (currently in the peer review queue) is slowly 
gaining an asynchronous batch hash engine. It's a bit different from 
your normal hash engine, because it can do things like use SIMD to 
process four SHA256 streams in parallel, and then using AFIO's 
closure engine to parallelise that 4-SHA256 processing across 
multiple cores i.e. achieve sixteen parallel SHA256 processing 
streams. This lets one drop the normal 14.9 cycles/byte down to 
around 1.4 cycles/byte amortised for SHA256 [1], a big win. The batch 
hash engine uses a compile-time plugin system, so it can be 
arbitrarily extended with other hash implementations if suitably 
rewritten to fit.

Of course AFIO may not pass peer review, so any work done here may be 
moot. That therefore should not inhibit your efforts.

In case anyone wants to know "when will it be ready?", well being 
unemployed and having to relocate back to Europe has punched a huge 
hole in my productivity. Once I'm back (January) I would expect 
things to move far more swiftly. I should have something which passes 
basic unit tests this month though - I already have a proof of 
concept working, it's just converting it into something not so hacked 
together.

[1] These figures are for an Intel i7-3770K running x64. Other CPUs 
vary hugely (e.g. ARM, whose NEON unit is not well scheduled by GCC 
or clang).

Niall

-- 
Currently unemployed and looking for work.
Work Portfolio: http://careers.stackoverflow.com/nialldouglas/