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Beacon chain simulator

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Mikhail Kalinin edited this page Mar 11, 2019 · 24 revisions

Beacon chain simulator

A simulator is a tool that runs a standalone beacon chain instance with a number of assumptions and limitations. The main goal of simulator is to try beacon chain consensus algorithms executing in different circumstances like with a 100% honest validator set and some bad actors in it, network drops and delays. The other goal is to measure performance, check out bottlenecks and look for ways of design improvement and optimizations.

Parameters

There is a number of parameters affecting beacon chain runtime. Some of them are hard coded in the simulator but valuable consensus parameters are configurable by the user.

Built-in parameters

There is a set of immutable simulation parameters:

  • time - beacon chain time is driven by a routine called ControlledSchedulers which method addTime adds a slot to overall system time and processes all the events that correspond to this time slot; during simulation addTime is triggered by infinite loop adding 1 millisecond in each iteration.
  • network - there is a special storage in memory that aids network simulation; attestations and blocks are simply propagated to all peers in the "network".
  • database - simulator doesn't store anything on disk, each time it starts with clean in-memory database.
  • eth1 chain - simulator starts with a set of initial validators defined by user, validator registration is not handled by simulation.

Configurable parameters

  • genesis-time - sets Genesis time in seconds using Unix timestamp notation.
  • seed - an integer number that will be used as a seed to generate credentials of initial validator set, if not specified random value will be used; setting this parameter preserves validator credentials between simulations.
  • bls-verify - whether BLS verification is enabled during simulation or not, false by default; this flag doesn't affect BLS signature creation, it only skips its verification part allowing simulation to run faster.
  • peers - describes groups of peers with different behavior that are participating in simulation.

Peer groups

  • validator - a flag indicating whether this is a validator group or chain observers that passively imports the chain.
  • count - number of peers in the group.

This parameter list is going to be extended in the future versions to simulate network issues and dishonest validator actions.

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