More precise gasWanted

[tomtau]

Proposal:
Use more precise bounds for gasWanted via constant time estimates and/or linear time amortization analysis.

Current behavior:
Right now, it uses the user's set gas limit or capping it by an arbitrary number:

ethermint/app/ante/eth.go

Line 201 in 8e2c652

gasWanted += txData.GetGas()

In the future with ABCI++, it may be possible to use gasUsed, but that's not possible now.

Desired behavior:
Ideally, Ethermint could use more tighter bounds without the full EVM execution:

• some constant checks: https://github.com/ethereum/go-ethereum/blob/3e693e1ef6e2da69847a30a14808b327aa07060e/internal/ethapi/api.go#L1022 (many of those are more for max bounds but there may be some more precise / more meaningful values taken from the state)
• linear time analysis: https://www.cs.cmu.edu/~ankushd/docs/move20.pdf (there may be others such as https://arxiv.org/abs/1912.11929 but not sure about their complexity )

Use case:

• better block utilization
• less likely to go over the maximum block gas limit

Requests may be closed if we're not actively planning to work on them.

[tomtau]

https://github.com/ethereum/evmone/blob/master/docs/efficient_gas_calculation_algorithm.md