diff options
Diffstat (limited to 'core/chain_util.go')
| -rw-r--r-- | core/chain_util.go | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/core/chain_util.go b/core/chain_util.go index 326bf13fb..104670195 100644 --- a/core/chain_util.go +++ b/core/chain_util.go @@ -69,17 +69,30 @@ func CalcTD(block, parent *types.Block) *big.Int { // CalcGasLimit computes the gas limit of the next block after parent. // The result may be modified by the caller. +// This is miner strategy, not consensus protocol. func CalcGasLimit(parent *types.Block) *big.Int { - decay := new(big.Int).Div(parent.GasLimit(), params.GasLimitBoundDivisor) + // contrib = (parentGasUsed * 3 / 2) / 1024 contrib := new(big.Int).Mul(parent.GasUsed(), big.NewInt(3)) contrib = contrib.Div(contrib, big.NewInt(2)) contrib = contrib.Div(contrib, params.GasLimitBoundDivisor) + // decay = parentGasLimit / 1024 -1 + decay := new(big.Int).Div(parent.GasLimit(), params.GasLimitBoundDivisor) + decay.Sub(decay, big.NewInt(1)) + + /* + strategy: gasLimit of block-to-mine is set based on parent's + gasUsed value. if parentGasUsed > parentGasLimit * (2/3) then we + increase it, otherwise lower it (or leave it unchanged if it's right + at that usage) the amount increased/decreased depends on how far away + from parentGasLimit * (2/3) parentGasUsed is. + */ gl := new(big.Int).Sub(parent.GasLimit(), decay) gl = gl.Add(gl, contrib) - gl = gl.Add(gl, big.NewInt(1)) gl.Set(common.BigMax(gl, params.MinGasLimit)) + // however, if we're now below the target (GenesisGasLimit) we increase the + // limit as much as we can (parentGasLimit / 1024 -1) if gl.Cmp(params.GenesisGasLimit) < 0 { gl.Add(parent.GasLimit(), decay) gl.Set(common.BigMin(gl, params.GenesisGasLimit)) |