accumulator/pollard: Speedups for pollard #176
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dergoegge
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Jul 27, 2020
dergoegge
reviewed
Jul 27, 2020
Biggest thing done is to match known hashes in the pollard nodes when hashing for parents from the given batchproof, saving on sha256 hashes.
kcalvinalvin
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Tested, looks good. Could have even more speedups combined with #177, or further TTL / caching after that PR. |
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Things done:
Different implementation of Match known hashes in pollard #3 where the already known hashes of parents were matched, saving sha256 hashes. Instead of going through all the nodes to the path of the leaf being verified, in this implementation just looks for the polNode at the parent position. New method on pollard
readPoswas needed as reading fromgrabPoscreated nil hashable nodes.Various comments and small code fixes.
In my testing to block 600,000 on testnet3, the speedups were around 5%. However, when tested on blocks with lower height, the speedups were even less. So more hashing goes on as the tree gets bigger, leading to bigger savings. The matched hashes to the tip of the default server was 160,716,082 hashes and the unmatched hashes were 55,700,940 hashes. So this is around 75% of potential sha computation saved.