Charge for the fields of transaction as part of min_fee

[Voxelot]

Problem overview

There are several areas of transaction verification that do not have accurate costing. While we have a good framework for pricing opcodes now, our costing of the transaction min fee leaves more to be desired.

Currently the min fee of a transaction is solely based on the amount of chargeable serialized bytes. However, this is likely insufficient for accurate transaction metering. The risks of inaccurate metering are:

• Liveness failures (i.e. skipped consensus rounds)
• Unsynchronizable nodes
• Unanticipated DA expenses, leaving the L1 committer to pick up the tab.

Solution

We've already found several places where we undercharge users FuelLabs/fuel-core#1418.

There's likely more hot spots in transaction validation that aren't captured by our current byte pricing structure. We should investigate this further by building a fuzzing framework FuelLabs/fuel-core#1402 that detects any discrepancies between transaction base cost vs validation time in gas units (i.e. IntoChecked::into_checked) + disk space delta after execution #601. This should help capture subtle differences in disk footprint & I/O requirements such as contract bytecode being duplicated into two tables instead unlike the rest of the transaction bytes.

The action list is:

• Create benchmarks to track the impact of each field on execution time.
  • Sanity check transaction min_fee gas prices by executing the block with pre-defined gas limit fuel-core#1387
  • Create a fuzzing tool for Checked<Tx> verification costing fuel-core#1402
  • Determine how much it takes to initialise the VM fuel-core#1442
• Identify fields that should be charged.
• Apply a new charging model to the codebase. It should affect the final min_fee of the transaction.
  • Charge transaction for fields that slow down block production fuel-core#1403
  • Investigate and start to charge for storage artifacts produced by transactions #601
  • Charge transaction for fields that slow down its verification fuel-core#1418
  • Implement I/O gas measurement fuel-core#1161
• Verify that a new prices/cost covers execution time.

[Voxelot]

Initial benchmarking shows we need to increase minimum fee based on predicates & per signature recovery, potentially adjust gas_per_byte / how bytes are metered.