Commit Graph

8 Commits

Author SHA1 Message Date
Etan Kissling ea97e93e74
accelerate `getShufflingRef` (#4911)
When an uncached `ShufflingRef` is requested, we currently replay state
which can take several seconds. Acceleration is possible by:

1. Start from any state with locked-in `get_active_validator_indices`.
   Any blocks / slots applied to such a state can only affect that
   result for future epochs, so are viable for querying target epoch.
   `compute_activation_exit_epoch(state.slot.epoch) > target.epoch`

2. Determine highest common ancestor among `state` and `target.blck`.
   At the ancestor slot, same rules re `get_active_validator_indices`.
   `compute_activation_exit_epoch(ancestorSlot.epoch) > target.epoch`

3. We now have a `state` that shares history with `target.blck` up
   through a common ancestor slot. Any blocks / slots that the `state`
   contains, which are not part of the `target.blck` history, affect
   `get_active_validator_indices` at epochs _after_ `target.epoch`.

4. Select `state.randao_mixes[N]` that is closest to common ancestor.
   Either direction is fine (above / below ancestor).

5. From that RANDAO mix, mix in / out all RANDAO reveals from blocks
   in-between. This is just an XOR operation, so fully reversible.
   `mix = mix xor SHA256(blck.message.body.randao_reveal)`

6. Compute the attester dependent slot from `target.epoch`.
   `if epoch >= 2: (target.epoch - 1).start_slot - 1 else: GENESIS_SLOT`

7. Trace back from `target.blck` to the attester dependent slot.
   We now have the destination for which we want to obtain RANDAO.

8. Mix in all RANDAO reveals from blocks up through the `dependentBlck`.
   Same method, no special handling necessary for epoch transitions.

9. Combine `get_active_validator_indices` from `state` at `target.epoch`
   with the recovered RANDAO value at `dependentBlck` to obtain the
   requested shuffling, and construct the `ShufflingRef` without replay.

* more tests and simplify logic

* test with different number of deposits per branch

* Update beacon_chain/consensus_object_pools/blockchain_dag.nim

Co-authored-by: Jacek Sieka <jacek@status.im>

* `commonAncestor` tests

* lint

---------

Co-authored-by: Jacek Sieka <jacek@status.im>
2023-05-12 19:36:59 +02:00
tersec a07d14cd99
remove unused imports in tests/ (#3713) 2022-06-07 17:05:06 +00:00
Jacek Sieka a3bd01b58d
move dependent root computations to `BeaconState` / `EpochRef` (#3478)
* fewer deps on `BlockRef` traversal in anticipation of pruning
* allows identifying EpochRef:s by their shuffling as a first step of
* tighten error handling around missing blocks

using the zero hash for signalling "missing block" is fragile and easy
to miss - with checkpoint sync now, and pruning in the future, missing
blocks become "normal".
2022-03-15 09:24:55 +01:00
Jacek Sieka 4363215a32
relax `BlockRef` database assumptions (#3472)
* remove `getForkedBlock(BlockRef)` which assumes block data exists but
doesn't support archive/backfilled blocks
* fix REST `/eth/v1/beacon/headers` request not returning
archive/backfilled blocks
* avoid re-encoding in REST block SSZ requests (using `getBlockSSZ`)
2022-03-11 13:08:17 +01:00
Jacek Sieka 805e85e1ff
time: spring cleaning (#3262)
Time in the beacon chain is expressed relative to the genesis time -
this PR creates a `beacon_time` module that collects helpers and
utilities for dealing the time units - the new module does not deal with
actual wall time (that's remains in `beacon_clock`).

Collecting the time related stuff in one place makes it easier to find,
avoids some circular imports and allows more easily identifying the code
actually needs wall time to operate.

* move genesis-time-related functionality into `spec/beacon_time`
* avoid using `chronos.Duration` for time differences - it does not
support negative values (such as when something happens earlier than it
should)
* saturate conversions between `FAR_FUTURE_XXX`, so as to avoid
overflows
* fix delay reporting in validator client so it uses the expected
deadline of the slot, not "closest wall slot"
* simplify looping over the slots of an epoch
* `compute_start_slot_at_epoch` -> `start_slot`
* `compute_epoch_at_slot` -> `epoch`

A follow-up PR will (likely) introduce saturating arithmetic for the
time units - this is merely code moves, renames and fixing of small
bugs.
2022-01-11 11:01:54 +01:00
Jacek Sieka 6f7e0e3393
REST cleanups (#3255)
* REST cleanups

* reject out-of-range committee requests
* print all hex values as lower-case
* allow requesting state information by head state root
* turn `DomainType` into array (follow spec)
* `uint_to_bytesXX` -> `uint_to_bytes` (follow spec)
* fix wrong dependent root in `/eth/v1/validator/duties/proposer/`
* update documentation - `--subscribe-all-subnets` is no longer needed
when using the REST interface with validator clients
* more fixes
* common helpers for dependent block
* remove test rules obsoleted by more strict epoch tests
* fix trailing commas

* Update docs/the_nimbus_book/src/rest-api.md
* Update docs/the_nimbus_book/src/rest-api.md

Co-authored-by: sacha <sacha@status.im>
2022-01-08 22:06:34 +02:00
Jacek Sieka 7ec97a6b35
Fix missing checkpoint states` (#3225)
With the right sequence of events (for example a REST request or a
validation), it can happen that the first traversal across a state
checkpoint boundary is done without storing that state on disk - this
causes problens when replaying states, because now states may be missing
from the database.

Here, we simply avoid using the caches when advancing a state that will
go into the database, ensuring that the information lost during caching
always is permanently stored.

* fix recursion bug in `isProposed`
2021-12-30 12:33:03 +01:00
Jacek Sieka 9f27f0d97c
BlockId reform (#3176)
* BlockId reform

Introduce `BlockId` that helps track a root/slot pair - this prepares
the codebase for backfilling and handling out-of-dag blocks

* move block dag code to separate module
* fix finalised state root in REST event stream
* fix finalised head computation on head update, when starting from
checkpoint
* clean up chaindag init
* revert `epochAncestor` change in introduced in #3144 that would return
an epoch ancestor from the canoncial history instead of the given
history, causing `EpochRef` keys to point to the wrong block
2021-12-09 19:06:21 +02:00