[ZcF-general] Grant project update - new PoW scheme

[Solar Designer]

Hi,

This is my second status report on GrantProposals-2018Q2 #25 "review,
tweaks, and maybe design of a new PoW scheme for Zcash."

https://github.com/ZcashFoundation/GrantProposals-2018Q2/issues/25

Unfortunately, I didn't put as much time into this project as I would
have liked to.  That said, a few things did advance since last update:

On Sun, Jan 06, 2019 at 03:13:32PM +0100, Solar Designer wrote:
> - Optionally, purchase and installation of new GPUs and required software
> 
> Since Zcash Foundation chose to fund this proposed upgrade of Openwall's
> HPC Village ("a project of Openwall where we provide Open Source
> developers with remote access to a system with NVIDIA and AMD GPUs, and
> Intel Xeon Phi") - thanks! - we looked into the currently available and
> reasonable upgrade options and ended up ordering a GTX 1080 (a short
> enough card to use a slot that we didn't have other good use for, so we
> can leave more other GPUs in the machine) and a Vega 64 to be installed
> later in January.

These two new GPUs have been installed and are now available to
ourselves and the larger Open Source community in our HPC Village:

https://openwall.info/wiki/HPC/Village

We've also updated to CUDA 10.0 and AMDGPU-PRO 18.50.  We first tested
the updated setup with John the Ripper and Hashcat, and then I proceeded
to use this setup to test ProgPOW vs. Ethash (because that's where
ProgPOW was forked from) taking notes in the process.

I've just posted some results of this testing as two issues on ProgPOW
GitHub, suggesting that they add this or/and other related information
to the documentation:

Build instructions
https://github.com/ifdefelse/ProgPOW/issues/27

Benchmark results
https://github.com/ifdefelse/ProgPOW/issues/26

The benchmark results show that the two new GPUs were actually required.
The older GPUs also still present in the machine (Titan Kepler and Titan
X Maxwell) achieve good speeds at 1 GB DAG size, but no longer achieve
sane speeds at the 3 GB DAG size currently used by Ethereum (and
presumably Zcash would use no smaller than that if it switches to
ProgPOW).  Those older GPUs do have more than enough memory (6 GB and
12 GB, respectively), but somehow are several times slower than current
ones at this test.  We might investigate this later.  Maybe some tuning
will help.

> Unexpectedly, I also ended up looking into Equihash parameters and
> making suggestions again, as it appears Zcash's temporary second PoW for
> Blossom will be merely another Equihash instantiation, and this needs to
> be decided on ASAP:
> 
> [Blossom NU] Write spec for Harmony Mining
> https://github.com/zcash/zcash/issues/3672

Zcash no longer plans on having a temporary second PoW in Blossom, so
the discussion on that issue ceased.

> whereas the work more obviously falling under this grant will probably
> fit under:
> 
> choose new PoW for Zcash 4.0 (NU3)
> https://github.com/zcash/zcash/issues/3761

Alexander