Commit Graph

3 Commits

Author SHA1 Message Date
Jordan Hrycaj ca07c40a48
Fearture/poa clique tuning (#765)
* Provide API

details:
  API is bundled via clique.nim.

* Set extraValidation as default for PoA chains

why:
  This triggers consensus verification and an update of the list
  of authorised signers. These signers are integral part of the
  PoA block chain.

todo:
  Option argument to control validation for the nimbus binary.

* Fix snapshot state block number

why:
  Using sub-sequence here, so the len() function was wrong.

* Optional start where block verification begins

why:
  Can speed up time building loading initial parts of block chain. For
  PoA, this allows to prove & test that authorised signers can be
  (correctly) calculated starting at any point on the block chain.

todo:
  On Goerli around blocks #193537..#197568, processing time increases
  disproportionally -- needs to be understand

* For Clique test, get old grouping back (7 transactions per log entry)

why:
  Forgot to change back after troubleshooting

* Fix field/function/module-name misunderstanding

why:
  Make compilation work

* Use eth_types.blockHash() rather than utils.hash() in Clique modules

why:
  Prefer lib module

* Dissolve snapshot_misc.nim

details:
  .. into clique_verify.nim (the other source file clique_unused.nim
  is inactive)

* Hide unused AsyncLock in Clique descriptor

details:
  Unused here but was part of the Go reference implementation

* Remove fakeDiff flag from Clique descriptor

details:
  This flag was a kludge in the Go reference implementation used for the
  canonical tests. The tests have been adapted so there is no need for
  the fakeDiff flag and its implementation.

* Not observing minimum distance from epoch sync point

why:
  For compiling PoA state, the go implementation will walk back to the
  epoch header with at least 90000 blocks apart from the current header
  in the absence of other synchronisation points.

  Here just the nearest epoch header is used. The assumption is that all
  the checkpoints before have been vetted already regardless of the
  current branch.

details:
  The behaviour of using the nearest vs the minimum distance epoch is
  controlled by a flag and can be changed at run time.

* Analysing processing time (patch adds some debugging/visualisation support)

why:
  At the first half million blocks of the Goerli replay, blocks on the
  interval #194854..#196224 take exceptionally long to process, but not
  due to PoA processing.

details:
  It turns out that much time is spent in p2p/excecutor.processBlock()
  where the elapsed transaction execution time is significantly greater
  for many of these blocks.

  Between the 1371 blocks #194854..#196224 there are 223 blocks with more
  than 1/2 seconds execution time whereas there are only 4 such blocks
  before and 13 such after this range up to #504192.

* fix debugging symbol in clique_desc (causes CI failing)

* Fixing canonical reference tests

why:
  Two errors were introduced earlier but ovelooked:
   1. "Remove fakeDiff flag .." patch was incomplete
   2. "Not observing minimum distance .." introduced problem w/tests 23/24

details:
  Fixing 2. needed to revert the behaviour by setting the
  applySnapsMinBacklog flag for the Clique descriptor. Also a new
  test was added to lock the new behaviour.

* Remove cruft

why:
  Clique/PoA processing was intended to take place somewhere in
  executor/process_block.processBlock() but was decided later to run
  from chain/persist_block.persistBlock() instead.

* Update API comment

* ditto
2021-07-30 15:06:51 +01:00
Jordan Hrycaj a0d0e35a70
Renamed source file clique_utils => clique_helpers (#762)
* Renamed source file clique_utils => clique_helpers

why:
  New name is more in line with other modules where local libraries
  are named similarly.

* re-implemented PoA verification module as clique_verify.nim

details:
  The verification code was ported from the go sources and provisionally
  stored in the clique_misc.nim source file.

todo:
  Bring it to life.

* re-design Snapshot descriptor as: ref object

why:
  Avoids some copying descriptor objects

details:
  The snapshot management in clique_snapshot.nim has been cleaned up.

todo:
  There is a lot of unnecessary copying & sub-list manipulation of
  seq[BlockHeader] lists which needs to be simplified by managing
  index intervals.

* optimised sequence handling for Clique/PoA

why:
  To much ado about nothing

details:
  * Working with shallow sequences inside PoA processing avoids
    unnecessary copying.
  * Using degenerate lists in the cliqueVerify() batch where only the
    parent (and no other ancestor) is needed.

todo:
  Expose only functions that are needed, shallow sequences should be
  handles with care.

* fix var-parameter function argument

* Activate PoA engine -- currently proof of concept

details:
  PoA engine is activated with newChain(extraValidation = true) applied
  to a PoA network.

status and todo:
  The extraValidation flag on the Chain object can be set at a later
  state which allows to pre-load parts of the block chain without
  verification. Setting it later will only go back the block chain to
  the latest epoch checkpoint. This is inherent to the Clique protocol,
  needs testing though.

  PoA engine works in fine weather mode on Goerli replay. With the
  canonical eip-225 tests, there are quite a few fringe conditions
  that fail. These can easily fudged over to make things work but need
  some more work to understand and correct properly.

* Make the last offending verification header available

why:
  Makes some fringe case tests work.

details:
  Within a failed transaction comprising several blocks, this
  feature help to identify the offending block if there was a
  PoA verification error.

* Make PoA header verifier store the final snapshot

why:
  The last snapshot needed by the verifier is the one of the parent but
  the list of authorised signer is derived from the current snapshot. So
  updating to the latest snapshot provides the latest signers list.

details:
  Also, PoA processing has been implemented as transaction in
  persistBlocks() with Clique state rollback.

  Clique tests succeed now.

* Avoiding double yields in iterator => replaced by template

why:
  Tanks to Andri who observed it (see #762)

* Calibrate logging interval and fix logging event detection

why:
  Logging interval as copied from Go implementation was too large and
  needed re-calibration. Elapsed time calculation was bonkers, negative
  the wrong way round.
2021-07-21 14:31:52 +01:00
Jordan Hrycaj cfe955c962
Feature/implement poa processing (#748)
* re-shuffled Clique functions

why:
  Due to the port from the go-sources, the interface logic is not optimal
  for nimbus. The main visible function is currently snapshot() and most
  of the _procurement_ of this function result has been moved to a
  sub-directory.

* run eip-225 Clique test against p2p/chain.persistBlocks()

why:
  Previously, loading the test block chains was fugdged with the purpose
  only to fill the database. As it is now clear how nimbus works on
  Goerli, the same can be achieved with a more realistic scenario.

details:
  Eventually these tests will be pre-cursor to the reply tests for the
  Goerli chain supporting TDD approach with more simple cases.

* fix exception annotations for executor module

why:
  needed for exception tracking

details:
  main annoyance are vmState methods (in state.nim) which potentially
  throw a base level Exception (a proc would only throws CatchableError)

* split p2p/chain into sub-modules and fix exception annotations

why:
  make space for implementing PoA stuff

* provide over-loadable Clique PRNG

why:
  There is a PRNG provided for generating reproducible number sequences.
  The functions which employ the PRNG to generate time slots were ported
  ported from the go-implementation. They are currently unused.

* implement trusted signer assembly in p2p/chain.persistBlocks()

details:
  * PoA processing moved there at the end of a transaction. Currently,
   there is no action (eg. transaction rollback) if this fails.
  * The unit tests with staged blocks work ok. In particular, there should
    be tests with to-be-rejected blocks.
  * TODO: 1.Optimise throughput/cache handling; 2.Verify headers

* fix statement cast in pool.nim

* added table features to LRU cache

why:
  Clique uses the LRU cache using a mixture of volatile online items
  from the LRU cache and database checkpoints for hard synchronisation.
  For performance, Clique needs more table like features.

details:
  First, last, and query key added, as well as efficient random delete
  added. Also key-item pair iterator added for debugging.

* re-factored LRU snapshot caching

why:
  Caching was sub-optimal (aka. bonkers) in that it skipped over memory
  caches in many cases and so mostly rebuild the snapshot from the
  last on-disk checkpoint.

details;
  The LRU snapshot toValue() handler has been moved into the module
  clique_snapshot. This is for the fact that toValue() is not supposed
  to see the whole LRU cache database. So there must be a higher layer
  working with the the whole LRU cache and the on-disk checkpoint
  database.

also:
  some clean up

todo:
  The code still assumes that the block headers are valid in itself. This
  is particular important when an epoch header (aka re-sync header) is
  processed as it must contain the PoA result of all previous headers.

  So blocks need to be verified when they come in before used for PoA
  processing.

* fix some snapshot cache fringe cases

why:
  Must not index empty sequences in clique_snapshot module
2021-07-14 16:13:27 +01:00