SIP 20: Gas Optimisations Source

AuthorClinton Ennis
Discussions-Tohttps://discord.gg/CDTvjHY
StatusImplemented
Created2019-10-15

Simple Summary

Optimize the gas on critical, high use functions that are used almost weekly by users that currently cost a lot in gas usage.

Abstract

To make transactions cost less gas usage for Synthetix users, a gitcoin bounty was created to R&D gas optimisations on the upgradable contracts across these high use functions;

  • Synthetix.issueSynths (& issueMaxSynths)
  • Synthetix.burnSynths
  • Synthetix.exchange
  • Synthetix.transfer (& transferFrom)
  • FeePool.claimFees
  • ExchangeRates.updateRates (onlyOracle function)

Excludes

  • using solidity compilers optimize runs
  • ownerOnly functions

The bounty resulted in several PRs for the team to validate and integrate into the system with some high value gas savings achieved.

Motivation

Public functions

For SNX holders/mintr users, reducing the cost of maintaining SNX collateralisation ratio via mint & burn, claiming fees and rewards and token transfers and Synthetix.exchange trades.

onlyOracle functions

Reduce the cost of the ExchangeRates.updateRates function in storing pricing data onching will save the foundation in ETH running costs for the oracle.

Specification

(@k06a) Gas Opt results

alpha (2eaef0dddf95d6c0e3a1acd4a96482aab8143d30):

·--------------------------------------------------------|---------------------------|-------------|----------------------------·
|          Solc version: 0.4.25+commit.59dbf8f1          ·  Optimizer enabled: true  ·  Runs: 200  ·  Block limit: 8000000 gas  │
·························································|···························|·············|·····························
|  Methods                                               ·               4 gwei/gas                ·       180.56 usd/eth       │
························|································|·············|·············|·············|··············|··············
|  Contract             ·  Method                        ·  Min        ·  Max        ·  Avg        ·  # calls     ·  usd (avg)  │
························|································|·············|·············|·············|··············|··············
|  Synthetix            ·  issueSynths                   ·     306850  ·     582310  ·     423915  ·         284  ·       0.31  │
························|································|·············|·············|·············|··············|··············
|  Synthetix            ·  burnSynths                    ·     476976  ·     664025  ·     561884  ·          99  ·       0.41  │
························|································|·············|·············|·············|··············|··············
|  ExchangeRates        ·  updateRates                   ·      56015  ·    6535679  ·     117042  ·         486  ·       0.08  │
························|································|·············|·············|·············|··············|··············
|  FeePool              ·  claimFees                     ·     390436  ·     514240  ·     441358  ·          41  ·       0.32  │
························|································|·············|·············|·············|··············|··············
|  Synthetix            ·  exchange                      ·      59871  ·     249564  ·     224765  ·          45  ·       0.16  │
························|································|·············|·············|·············|··············|··············

optimize/rates-storage (1e2196d59bbd921bce144195e00d198548c64c28):

·--------------------------------------------------------|---------------------------|-------------|----------------------------·
|          Solc version: 0.4.25+commit.59dbf8f1          ·  Optimizer enabled: true  ·  Runs: 200  ·  Block limit: 8000000 gas  │
·························································|···························|·············|·····························
|  Methods                                               ·               4 gwei/gas                ·       180.56 usd/eth       │
························|································|·············|·············|·············|··············|··············
|  Contract             ·  Method                        ·  Min        ·  Max        ·  Avg        ·  # calls     ·  usd (avg)  │
························|································|·············|·············|·············|··············|··············
|  Synthetix            ·  issueSynths                   ·     307688  ·     584059  ·     426344  ·         284  ·       0.31  │
························|································|·············|·············|·············|··············|··············
|  Synthetix            ·  burnSynths                    ·     479100  ·     666231  ·     564608  ·          99  ·       0.41  │
························|································|·············|·············|·············|··············|··············
|  ExchangeRates        ·  updateRates                   ·      46830  ·    3566459  ·      84580  ·         486  ·       0.06  │
························|································|·············|·············|·············|··············|··············
|  FeePool              ·  claimFees                     ·     391534  ·     515471  ·     442495  ·          41  ·       0.32  │
························|································|·············|·············|·············|··············|··············
|  Synthetix            ·  exchange                      ·      59871  ·     249871  ·     225068  ·          45  ·       0.16  │
························|································|·············|·············|·············|··············|··············

Test Cases

Implementation

https://github.com/Synthetixio/synthetix/commit/05c42daefb282a49f791e7e626e10cf1f8352f36

Copyright and related rights waived via CC0.