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Jacek Sieka 233d756518
Logging and startup improvements (#3038) 
* Logging and startup improvements

Color support for released binaries!

* startup scripts no longer log to file by default - this only affects
source builds - released binaries don't support file logging
* add --log-stdout option to control logging to stdout (colors, json)
* detect tty:s vs redirected logs and log accordingly
* add option to disable log colors at runtime
* simplify several "common" logs, showing the most important information
earlier and more clearly
* remove line numbers / file information / tid - these take up space and
are of little use to end users
  * still enabled in debug builds and tools
* remove `testnet_servers_image` compile-time option
* server images, released binaries and compile-from-source now offer
the same behaviour and features
* fixes https://github.com/status-im/nimbus-eth2/issues/2326
* fixes https://github.com/status-im/nimbus-eth2/issues/1794
* remove instanteneous block speed from sync message, keeping only
average

before:

```
INF 2021-10-28 16:45:59.000+02:00 Slot start                                 topics="beacnde" tid=386429 file=nimbus_beacon_node.nim:884 lastSlot=2384027 wallSlot=2384028 delay=461us84ns peers=0 head=75a10ee5:3348 headEpoch=104 finalized=cd6804ba:3264 finalizedEpoch=102 sync="wwwwwwwwww:0:0.0000:0.0000:00h00m (3348)"
INF 2021-10-28 16:45:59.046+02:00 Slot end                                   topics="beacnde" tid=386429 file=nimbus_beacon_node.nim:821 slot=2384028 nextSlot=2384029 head=75a10ee5:3348 headEpoch=104 finalizedHead=cd6804ba:3264 finalizedEpoch=102 nextAttestationSlot=-1 nextProposalSlot=-1 nextActionWait=n/a
```

after:

```
INF 2021-10-28 22:43:23.033+02:00 Slot start                                 topics="beacnde" slot=2385815 epoch=74556 sync="DDPDDPUDDD:10:5.2258:01h19m (2361088)" peers=37 head=eacd2dae:2361096 finalized=73782:a4751487 delay=33ms687us715ns
INF 2021-10-28 22:43:23.291+02:00 Slot end                                   topics="beacnde" slot=2385815 nextActionWait=n/a nextAttestationSlot=-1 nextProposalSlot=-1 head=eacd2dae:2361096
```

* fix comment

* documentation updates

* mention `--log-file` may be deprecated in the future
* update various docs
 		2021-11-02 18:06:36 +01:00
..
README.md Consolidate modules by areas [part 1] (#2365) 2021-03-02 11:27:45 +01:00
request_manager.nim import cleanup (#2997) 2021-10-19 16:09:26 +02:00
sync_manager.nim Logging and startup improvements (#3038) 2021-11-02 18:06:36 +01:00
sync_protocol.nim nim-libp2p auto bump (#2840) 2021-10-21 13:01:29 +02:00

README.md

Block syncing

This folder holds all modules related to block syncing

Block syncing uses ETH2 RPC protocol.

Reference diagram

Block flow

Eth2 RPC in

Blocks are requested during sync by the SyncManager.

Blocks are received by batch:

  • syncStep(SyncManager, index, peer)
  • in case of success:
    • push(SyncQueue, SyncRequest, seq[SignedBeaconBlock]) is called to handle a successful sync step. It calls validate(SyncQueue, SignedBeaconBlock)` on each block retrieved one-by-one
    • validate only enqueues the block in the SharedBlockQueue AsyncQueue[BlockEntry] but does no extra validation only the GossipSub case
  • in case of failure:
    • push(SyncQueue, SyncRequest) is called to reschedule the sync request.

Every second when sync is not in progress, the beacon node will ask the RequestManager to download all missing blocks currently in quarantaine.

  • via handleMissingBlocks
  • which calls fetchAncestorBlocks
  • which asynchronously enqueue the request in the SharedBlockQueue AsyncQueue[BlockEntry].

The RequestManager runs an event loop:

  • that calls fetchAncestorBlocksFromNetwork
  • which RPC calls peers with beaconBlocksByRoot
  • and calls validate(RequestManager, SignedBeaconBlock) on each block retrieved one-by-one
  • validate only enqueues the block in the AsyncQueue[BlockEntry] but does no extra validation only the GossipSub case

Weak subjectivity sync

Not implemented!

Comments

The validate procedure name for SyncManager and RequestManager as no P2P validation actually occurs.

Sync vs Steady State

During sync:

  • The RequestManager is deactivated
  • The syncManager is working full speed ahead
  • Gossip is deactivated

Bottlenecks during sync

During sync:

  • The bottleneck is clearing the SharedBlockQueue AsyncQueue[BlockEntry] via storeBlock which requires full verification (state transition + cryptography)

Backpressure

The SyncManager handles backpressure by ensuring that current_queue_slot <= request.slot <= current_queue_slot + sq.queueSize * sq.chunkSize.

  • queueSize is -1, unbounded, by default according to comment but all init paths uses 1 (?)
  • chunkSize is SLOTS_PER_EPOCH = 32

However the shared AsyncQueue[BlockEntry] itself is unbounded. Concretely:

  • The shared AsyncQueue[BlockEntry] is bounded for sync
  • The shared AsyncQueue[BlockEntry] is unbounded for validated gossip blocks

RequestManager and Gossip are deactivated during sync and so do not contribute to pressure.