lighthouse/consensus/state_processing/src/per_block_processing/altair
Paul Hauner 11d80a6a38 Optimise per_epoch_processing low-hanging-fruit (#3254)
## Issue Addressed

NA

## Proposed Changes

- Uses a `Vec` in `SingleEpochParticipationCache` rather than `HashMap` to speed up processing times at the cost of memory usage.
- Cache the result of `integer_sqrt` rather than recomputing for each validator.
- Cache `state.previous_epoch` rather than recomputing it for each validator.

### Benchmarks

Benchmarks on a recent mainnet state using #3252 to get timing.

#### Without this PR

```
lcli skip-slots --state-path /tmp/state-0x3cdc.ssz --partial-state-advance --slots 32 --state-root 0x3cdc33cd02713d8d6cc33a6dbe2d3a5bf9af1d357de0d175a403496486ff845e --runs 10
[2022-06-09T08:21:02Z INFO  lcli::skip_slots] Using mainnet spec
[2022-06-09T08:21:02Z INFO  lcli::skip_slots] Advancing 32 slots
[2022-06-09T08:21:02Z INFO  lcli::skip_slots] Doing 10 runs
[2022-06-09T08:21:02Z INFO  lcli::skip_slots] State path: "/tmp/state-0x3cdc.ssz"
SSZ decoding /tmp/state-0x3cdc.ssz: 43ms
[2022-06-09T08:21:03Z INFO  lcli::skip_slots] Run 0: 245.718794ms
[2022-06-09T08:21:03Z INFO  lcli::skip_slots] Run 1: 245.364782ms
[2022-06-09T08:21:03Z INFO  lcli::skip_slots] Run 2: 255.866179ms
[2022-06-09T08:21:04Z INFO  lcli::skip_slots] Run 3: 243.838909ms
[2022-06-09T08:21:04Z INFO  lcli::skip_slots] Run 4: 250.431425ms
[2022-06-09T08:21:04Z INFO  lcli::skip_slots] Run 5: 248.68765ms
[2022-06-09T08:21:04Z INFO  lcli::skip_slots] Run 6: 262.051113ms
[2022-06-09T08:21:05Z INFO  lcli::skip_slots] Run 7: 264.293967ms
[2022-06-09T08:21:05Z INFO  lcli::skip_slots] Run 8: 293.202007ms
[2022-06-09T08:21:05Z INFO  lcli::skip_slots] Run 9: 264.552017ms
```

#### With this PR:

```
lcli skip-slots --state-path /tmp/state-0x3cdc.ssz --partial-state-advance --slots 32 --state-root 0x3cdc33cd02713d8d6cc33a6dbe2d3a5bf9af1d357de0d175a403496486ff845e --runs 10
[2022-06-09T08:57:59Z INFO  lcli::skip_slots] Run 0: 73.898678ms
[2022-06-09T08:57:59Z INFO  lcli::skip_slots] Run 1: 75.536978ms
[2022-06-09T08:57:59Z INFO  lcli::skip_slots] Run 2: 75.176104ms
[2022-06-09T08:57:59Z INFO  lcli::skip_slots] Run 3: 76.460828ms
[2022-06-09T08:57:59Z INFO  lcli::skip_slots] Run 4: 75.904195ms
[2022-06-09T08:58:00Z INFO  lcli::skip_slots] Run 5: 75.53077ms
[2022-06-09T08:58:00Z INFO  lcli::skip_slots] Run 6: 74.745572ms
[2022-06-09T08:58:00Z INFO  lcli::skip_slots] Run 7: 75.823489ms
[2022-06-09T08:58:00Z INFO  lcli::skip_slots] Run 8: 74.892055ms
[2022-06-09T08:58:00Z INFO  lcli::skip_slots] Run 9: 76.333569ms
```

## Additional Info

NA
2022-06-10 04:29:28 +00:00
..
sync_committee.rs Optimise per_epoch_processing low-hanging-fruit (#3254) 2022-06-10 04:29:28 +00:00