Boost logo

Boost :

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

[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).


Currently unemployed and looking for work.
Work Portfolio:

Boost list run by bdawes at, gregod at, cpdaniel at, john at