## Proposed Changes
Add a new Cargo compilation profile called `maxperf` which enables more aggressive compiler optimisations at the expense of compilation time.
Some rough initial benchmarks show that this can provide up to a 25% reduction to run time for CPU bound tasks like block processing: https://docs.google.com/spreadsheets/d/15jHuZe7lLHhZq9Nw8kc6EL0Qh_N_YAYqkW2NQ_Afmtk/edit
The numbers in that spreadsheet compare the `consensus-context` branch from #3604 to the same branch compiled with the `maxperf` profile using:
```
PROFILE=maxperf make install-lcli
```
## Additional Info
The downsides of the maxperf profile are:
- It increases compile times substantially, which will particularly impact low-spec hardware. Compiling `lcli` is about 3x slower. Compiling Lighthouse is about 5x slower on my 5950X: 17m 38s rather than 3m 28s.
As a result I think we should not enable this everywhere by default.
- **Option 1**: enable by default for our released binaries. This gives the majority of users the fastest version of `lighthouse` possible, at the expense of slowing down our release CI. Source builds will continue to use the default `release` profile unless users opt-in to `maxperf`.
- **Option 2**: enable by default for source builds. This gives users building from source an edge, but makes them pay for it with compilation time.
I think I would prefer Option 1. I'll try doing some benchmarking to see how long a maxperf build of Lighthouse would take on GitHub actions.
Credit to Nicholas Nethercote for documenting these options in the Rust Performance Book: https://nnethercote.github.io/perf-book/build-configuration.html.
## Issue Addressed
Resolves#3516
## Proposed Changes
Adds a beacon fallback function for running a beacon node http query on all available fallbacks instead of returning on a first successful result. Uses the new `run_on_all` method for attestation and sync committee subscriptions.
## Additional Info
Please provide any additional information. For example, future considerations
or information useful for reviewers.
## Proposed Changes
Add some docs on checking the builder configuration, which is a frequently asked question on Discord.
## Additional Info
My text editor also insisted on stripping some trailing newlines, but can put 'em back if we want
## Issue Addressed
fixes lints from the last rust release
## Proposed Changes
Fix the lints, most of the lints by `clippy::question-mark` are false positives in the form of https://github.com/rust-lang/rust-clippy/issues/9518 so it's allowed for now
## Additional Info
## Issue Addressed
🐞 in which we don't actually unsubscribe from a random long lived subnet when it expires
## Proposed Changes
Remove code addressing a specific case in which we are subscribed to all subnets and handle the removal of the long lived subnet. I don't think the special case code is particularly important as, if someone is running with that many validators to be subscribed to all subnets, it should use `--subscribe-all-subnets` instead
## Additional Info
Noticed on some test nodes climbing bandwidth usage periodically (around 27hours, the time of subnet expirations) I'm running this code to test this does not happen anymore, but I think it should be good now
## Issue Addressed
NA
## Proposed Changes
This PR attempts to fix the following spurious CI failure:
```
---- store_tests::garbage_collect_temp_states_from_failed_block stdout ----
thread 'store_tests::garbage_collect_temp_states_from_failed_block' panicked at 'disk store should initialize: DBError { message: "Error { message: \"IO error: lock /tmp/.tmp6DcBQ9/cold_db/LOCK: already held by process\" }" }', beacon_node/beacon_chain/tests/store_tests.rs:59:10
```
I believe that some async task is taking a clone of the store and holding it in some other thread for a short time. This creates a race-condition when we try to open a new instance of the store.
## Additional Info
NA
## Issue Addressed
Resolves#3573
## Proposed Changes
Fix the bytecode for the deposit contract deployment transaction and value for deposit transaction in the execution engine integration tests. Also verify that all published transaction make it to the execution payload and have a valid status.
## Issue Addressed
NA
## Proposed Changes
This PR removes duplicated block root computation.
Computing the `SignedBeaconBlock::canonical_root` has become more expensive since the merge as we need to compute the merke root of each transaction inside an `ExecutionPayload`.
Computing the root for [a mainnet block](https://beaconcha.in/slot/4704236) is taking ~10ms on my i7-8700K CPU @ 3.70GHz (no sha extensions). Given that our median seen-to-imported time for blocks is presently 300-400ms, removing a few duplicated block roots (~30ms) could represent an easy 10% improvement. When we consider that the seen-to-imported times include operations *after* the block has been placed in the early attester cache, we could expect the 30ms to be more significant WRT our seen-to-attestable times.
## Additional Info
NA
## Issue Addressed
NA
## Proposed Changes
Fixes an issue introduced in #3574 where I erroneously assumed that a `crossbeam_channel` multiple receiver queue was a *broadcast* queue. This is incorrect, each message will be received by *only one* receiver. The effect of this mistake is these logs:
```
Sep 20 06:56:17.001 INFO Synced slot: 4736079, block: 0xaa8a…180d, epoch: 148002, finalized_epoch: 148000, finalized_root: 0x2775…47f2, exec_hash: 0x2ca5…ffde (verified), peers: 6, service: slot_notifier
Sep 20 06:56:23.237 ERRO Unable to validate attestation error: CommitteeCacheWait(RecvError), peer_id: 16Uiu2HAm2Jnnj8868tb7hCta1rmkXUf5YjqUH1YPj35DCwNyeEzs, type: "aggregated", slot: Slot(4736047), beacon_block_root: 0x88d318534b1010e0ebd79aed60b6b6da1d70357d72b271c01adf55c2b46206c1
```
## Additional Info
NA
## Proposed Changes
Improve the payload pruning feature in several ways:
- Payload pruning is now entirely optional. It is enabled by default but can be disabled with `--prune-payloads false`. The previous `--prune-payloads-on-startup` flag from #3565 is removed.
- Initial payload pruning on startup now runs in a background thread. This thread will always load the split state, which is a small fraction of its total work (up to ~300ms) and then backtrack from that state. This pruning process ran in 2m5s on one Prater node with good I/O and 16m on a node with slower I/O.
- To work with the optional payload pruning the database function `try_load_full_block` will now attempt to load execution payloads for finalized slots _if_ pruning is currently disabled. This gives users an opt-out for the extensive traffic between the CL and EL for reconstructing payloads.
## Additional Info
If the `prune-payloads` flag is toggled on and off then the on-startup check may not see any payloads to delete and fail to clean them up. In this case the `lighthouse db prune_payloads` command should be used to force a manual sweep of the database.
## Issue Addressed
https://github.com/ethereum/beacon-APIs/pull/222
## Proposed Changes
Update Lighthouse's randao verification API to match the `beacon-APIs` spec. We implemented the API before spec stabilisation, and it changed slightly in the course of review.
Rather than a flag `verify_randao` taking a boolean value, the new API uses a `skip_randao_verification` flag which takes no argument. The new spec also requires the randao reveal to be present and equal to the point-at-infinity when `skip_randao_verification` is set.
I've also updated the `POST /lighthouse/analysis/block_rewards` API to take blinded blocks as input, as the execution payload is irrelevant and we may want to assess blocks produced by builders.
## Additional Info
This is technically a breaking change, but seeing as I suspect I'm the only one using these parameters/APIs, I think we're OK to include this in a patch release.
## Issue Addressed
Closes https://github.com/sigp/lighthouse/issues/3556
## Proposed Changes
Delete finalized execution payloads from the database in two places:
1. When running the finalization migration in `migrate_database`. We delete the finalized payloads between the last split point and the new updated split point. _If_ payloads are already pruned prior to this then this is sufficient to prune _all_ payloads as non-canonical payloads are already deleted by the head pruner, and all canonical payloads prior to the previous split will already have been pruned.
2. To address the fact that users will update to this code _after_ the merge on mainnet (and testnets), we need a one-off scan to delete the finalized payloads from the canonical chain. This is implemented in `try_prune_execution_payloads` which runs on startup and scans the chain back to the Bellatrix fork or the anchor slot (if checkpoint synced after Bellatrix). In the case where payloads are already pruned this check only imposes a single state load for the split state, which shouldn't be _too slow_. Even so, a flag `--prepare-payloads-on-startup=false` is provided to turn this off after it has run the first time, which provides faster start-up times.
There is also a new `lighthouse db prune_payloads` subcommand for users who prefer to run the pruning manually.
## Additional Info
The tests have been updated to not rely on finalized payloads in the database, instead using the `MockExecutionLayer` to reconstruct them. Additionally a check was added to `check_chain_dump` which asserts the non-existence or existence of payloads on disk depending on their slot.
## Issue Addressed
Fixes a potential regression in memory fragmentation identified by @paulhauner here: https://github.com/sigp/lighthouse/pull/3371#discussion_r931770045.
## Proposed Changes
Immediately allocate a vector with sufficient size to hold all decoded elements in SSZ decoding. The `size_hint` is derived from the range iterator here:
2983235650/consensus/ssz/src/decode/impls.rs (L489)
## Additional Info
I'd like to test this out on some infra for a substantial duration to see if it affects total fragmentation.
## Issue Addressed
NA
## Proposed Changes
I've noticed that our block hashing times increase significantly after the merge. I did some flamegraph-ing and noticed that we're allocating a `Vec` for each byte of each execution payload transaction. This seems like unnecessary work and a bit of a fragmentation risk.
This PR switches to `SmallVec<[u8; 32]>` for the packed encoding of `TreeHash`. I believe this is a nice simple optimisation with no downside.
### Benchmarking
These numbers were computed using #3580 on my desktop (i7 hex-core). You can see a bit of noise in the numbers, that's probably just my computer doing other things. Generally I found this change takes the time from 10-11ms to 8-9ms. I can also see all the allocations disappear from flamegraph.
This is the block being benchmarked: https://beaconcha.in/slot/4704236
#### Before
```
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 980: 10.553003ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 981: 10.563737ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 982: 10.646352ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 983: 10.628532ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 984: 10.552112ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 985: 10.587778ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 986: 10.640526ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 987: 10.587243ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 988: 10.554748ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 989: 10.551111ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 990: 11.559031ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 991: 11.944827ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 992: 10.554308ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 993: 11.043397ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 994: 11.043315ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 995: 11.207711ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 996: 11.056246ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 997: 11.049706ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 998: 11.432449ms
[2022-09-15T21:44:19Z INFO lcli::block_root] Run 999: 11.149617ms
```
#### After
```
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 980: 14.011653ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 981: 8.925314ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 982: 8.849563ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 983: 8.893689ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 984: 8.902964ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 985: 8.942067ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 986: 8.907088ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 987: 9.346101ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 988: 8.96142ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 989: 9.366437ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 990: 9.809334ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 991: 9.541561ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 992: 11.143518ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 993: 10.821181ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 994: 9.855973ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 995: 10.941006ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 996: 9.596155ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 997: 9.121739ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 998: 9.090019ms
[2022-09-15T21:41:49Z INFO lcli::block_root] Run 999: 9.071885ms
```
## Additional Info
Please provide any additional information. For example, future considerations
or information useful for reviewers.
