`persist` is a hotspot when processing blocks because it is run at least
once per transaction and loops over the entire account cache every time.
Here, we introduce an extra `dirty` map that keeps track of all accounts
that need checking during `persist` which fixes the immediate
inefficiency, though probably this could benefit from a more thorough
review - we also get rid of the unused clearCache flag - we start with
a fresh cache on every fresh vmState.
* avoid unnecessary code hash comparisons
* avoid unnecessary copies when iterating
* use EMPTY_CODE_HASH throughout for code hash comparison
* Activate `LedgerRef` wrapper for `AccountsCache`
details:
`accounts_cache.nim` methods are indirectly processed by the wrapper
methods from `ledger.nim`.
This works for all sources except `test_state_db.nim` where the source
`accounts_cache.nim` is included (rather than imported) in order to
access objects privy to the very source.
* Provide facility to switch to a preselected `LedgerRef` type
details:
Can be set as suggestion when initialising `CommonRef`
* Update `CoreDb` test suite for better time tracking
details:
+ Allow time logging by pre-defined block intervals
+ Print `CoreDb`/`Ledger`profiling results (if enabled)
simplify EVM and delegete those things to accounts cache.
also no more manual state clearing, accounts cache will be
responsible for both collecting touched account and perform
state clearing.
Jacek Sieka
Jordan Hrycaj
jangko