WIP: validate transactions in parallel (no trie)

[miloserdow]

In the old flow, validation (including signature checks) happened inside verify_and_charge_transaction(). In the new flow, we first run parallel_validate_transactions() to validate and compute the transaction cost (including signature checks) in parallel. Only after a transaction passes validation do we call verify_and_charge_transaction() with the known cost.

graph TD;
    subgraph Old_Flow
    A[Runtime::apply]
    A-->B[self.process_transactions]
    B-->C[process_transaction]
    C-->D[verify_and_charge_transaction]
    D-->E[validate_transaction incl. signature]
    E-->|Valid|F[charge fees & finalize]
    E-->|Invalid|G[reject tx]
    end

    subgraph New_Flow
    A2[Runtime::apply]
    A2-->H[self.process_transactions]
    H-->|parallel|I[parallel_validate_transactions incl. signature]
    I-->|Valid, get cost|J[process_transaction]
    J-->K[verify_and_charge_transaction]
    K-->L[charge fees & finalize]
    I-->|Invalid|M[reject tx early]
    classDef threaded fill:#3240a8,stroke:#333,stroke-width:2px;
    class I threaded;
    end

Loading

(blue = running in parallel)

Testing

TBD