Introduction

As Tezos core developers, we DaiLambda and Tarides are working together to improve the perfomance of Tezos context: the version controlled store of Tezos block chain states.

DaiLambda has Plebeia, an append-only style data storage system based on Merkle Patricia binary tree. It is similar to Irmin by Tarides used for the Tezos context but incompatible. DaiLambda and Tarides have worked together to improve the performance of Tezos context subsystem, sometimes using what we have learned from Plebeia. For example, we provided the context tree for faster file access from the middle of the directory tree. Our context flattening done at Hangzhou upgrade speeded up the node by 30%. Recently, we have worked together to provide efficient Merkle proof encoding of Tezos context, using the idea of extender nodes of Plebeia, which will be used for the layer 2 solutions introduced in Tezos Jakarta upgrade.

Summary

The encoding of Micheline has several points to be improved. We propose to extend it to reduce the encoding size. Our quick survey shows that the possible size reduction is -22%.

The size reduction directly affects the storage burn fee. It should also improve the context disk access and reduces the storage access gas costs.

The new enconding is not yet implemented. The extension may have runtime overhead of the serialization but we expect it minimum.

Abstract

We are developing a technique of gradual migration to perform huge context modification at a protocol upgrade in multiple blocks to reduce the migration downtime ultimately to an unnoticeable level.

As the first example of this gradual migration, we plan to remove garbage files spendable left in 283K contract directories in Tezos mainnet. They should have been removed at the Babylone upgrade but some were left untouched until today.

Optz は Tezos ブロックチェーンのスマートコントラクトで使われている Michelson プログラムの最適化器です。 Optz は Michelson プログラムを入力として受け取り、(可能ならば)最適化を行って同じ動作をするより小さい、効率的な Michelson プログラムを出力します。

We have released Optz, an optimizer of Michelson programs, the base language for Tezos smart contract. It takes a Michelson code as input and then returns a smaller and more efficient equivalent code.

Optimization of Michelson opcode sequences

The optimization consists of 2 parts: rule-based transformation and optimal stack manipulation search by A* algorithm.

Rule based code transformation

Dozens of rewriting rules replace opcodes with better ones, such as:

PAIR; CDR  =>  DROP
   
DIP n { a }; DIP n { b }  =>  DIP n { a; b }
   
SWAP; op  =>  op  # when op is a commutative binary operator
   
NOT; IF { a } { b }  =>  IF { b } { a }

Search for the optimal stack manipulation sequences

A* algorithm finds the most optimal sequence of stack manipulation opcodes such as DROP, SWAP, DIG, DUG, DIP, DUP, and the push only opcodes like PUSH and EMPTY_SET. For example, the following opcode sequence :

DIG 1; DUP 1; DUG 2; PUSH c0; DIG 2; PUSH c1; DIG 4

is replaced with a shorter equivalent one:

[続きを読む]

Optz is an optimizer of Michelson programs, the base language for Tezos smart contract. It takes a Michelson code as input and then returns a smaller and more efficient equivalent code.

Optimization of Michelson opcode sequences

The optimization consists of 2 parts: rule-based transformation and optimal stack manipulation search by A* algorithm.

Rule based code transformation

Dozens of rewriting rules replace opcodes with better ones, such as:

PAIR; CDR  =>  DROP

DIP n { a }; DIP n { b }  =>  DIP n { a; b }

SWAP; op  =>  op  // when op is a commutative binary operator

NOT; IF { a } { b }  =>  IF { b } { a }

Search for the optimal stack manipulation sequences

After the rule-based transformation, A* algorithm finds the most optimal sequence of stack manipulation opcodes such as DROP, SWAP, DIG, DUG, DIP, DUP, CAR, CDR, PAIR, UNPAIR, and the push only opcodes like PUSH and EMPTY_SET. For example, the following opcode sequence found in an existing contract in Tezos mainnet: