clN22 - GPU accelerated 'zold-score/score_suffix'-replacement using OpenCL

clN22 is an experimental project for outsourcing CPU-intensive 'PoW'-workload running a Zold-node.

About

Please see the zold whitepaper for detailed information on Zold in general, and the score-system.

cln22-worker:

OpenCL 'zold-score' worker. 'Prefix' entered as input. Space separated, 'cln22' adds 6-character 'suffix' (a-z A-Z 0-9) and calculates sha256 hash of prefix+suffix. Starting with 'aaaaaa', proceeds to go through all possible suffices (ending with '999999') until the resulting hash ends with a set number of trailing zeroes (8). OpenCL kernel 'kernel22.cl' is built when program is launched for the first time. It is saved as '.clbin' -file, which is then used for all subsequent runs with the same device. Work group sizes are calculated according to what's available in the device used. Kernel is launched as 3-dimensional program. X, Y and Z are assigned to handle one character of 'suffix' each. Fourth character is resolved inside the kernel as well: If workgroup sizes are >= { 256, 256, 256 }, it is done in single execution. If not, by looping the kernel over as many times as needed. Remaining two characters are managed by host program. Time between kernel executions is measured and used to calculate performance, presented as 'MHash/s'.

cln22-zoldscore:

Modified 'zold-score/ScoreSuffix.cpp'. While 'zoldscore' normally uses randomly generated suffices and hashes them with CPU, 'cln22-zoldscore' calls 'cln22' or 'cln22-remote' instead. If it fails, it reverts back to normal 'random suffix with CPU'-opreating mode.

cln22-remote:

Client for 'cln22-manager' - fetch work items & return results.

How to get

Download:

Pre-built binaries (v0.931-020620) for Windows are available here.

Build:

OpenCL library, ICDs & headers are needed to build clN22. See this for instructions on Linux.

With GNU toolchain:

git clone https://github.com/ematkkona/clN22.git

cd clN22

make all

Usage:

'cln22' is automatically launched from cln22-remote - or from zold-score, if ran locally with the zold node.

Manual use:

Help:

./cln22

Sanity testing / benchmarking:

./cln22 testrun

Process an example workload:

./cln22 "InputStringWithCharactersAndNumbersABCabc123WithLengthOfSixtyToNinety" result.out log result.log