nimbus-eth2/beacon_chain/gossip_processing
Jacek Sieka b8a32419b8
async batch verification (+40% sig verification throughput) (#5176)
* async batch verification

When batch verification is done, the main thread is blocked reducing
concurrency.

With this PR, the new thread signalling primitive in chronos is used to
offload the full batch verification process to a separate thread
allowing the main threads to continue async operations while the other
threads verify signatures.

Similar to previous behavior, the number of ongoing batch verifications
is capped to prevent runaway resource usage.

In addition to the asynchronous processing, 3 addition changes help
drive throughput:

* A loop is used for batch accumulation: this prevents a stampede of
small batches in eager mode where both the eager and the scheduled batch
runner would pick batches off the queue, prematurely picking "fresh"
batches off the queue
* An additional small wait is introduced for small batches - this helps
create slightly larger batches which make better used of the increased
concurrency
* Up to 2 batches are scheduled to the threadpool during high pressure,
reducing startup latency for the threads

Together, these changes increase attestation verification throughput
under load up to 30%.

* fixup

* Update submodules

* fix blst build issues (and a PIC warning)

* bump

---------

Co-authored-by: Zahary Karadjov <zahary@gmail.com>
2023-08-03 11:36:45 +03:00
..
README.md update some consensus-specs ref URLs to v1.4.0-beta.0 (#5163) 2023-07-05 16:02:55 +00:00
batch_validation.nim async batch verification (+40% sig verification throughput) (#5176) 2023-08-03 11:36:45 +03:00
block_processor.nim async batch verification (+40% sig verification throughput) (#5176) 2023-08-03 11:36:45 +03:00
eth2_processor.nim async batch verification (+40% sig verification throughput) (#5176) 2023-08-03 11:36:45 +03:00
gossip_validation.nim async batch verification (+40% sig verification throughput) (#5176) 2023-08-03 11:36:45 +03:00
light_client_processor.nim automated consensus spec URL updating to v1.4.0-beta.0 (#5121) 2023-06-24 15:43:30 +00:00
optimistic_processor.nim remove Nim 1.2-compatible `push raise`s and update copyright notice years (#4528) 2023-01-20 14:14:37 +00:00

README.md

Gossip Processing

This folder holds a collection of modules to:

  • validate raw gossip data before
    • rebroadcasting it (potentially aggregated)
    • sending it to one of the consensus object pools

Validation

Gossip validation is different from consensus verification in particular for blocks.

There are multiple consumers of validated consensus objects:

  • a ValidationResult.Accept output triggers rebroadcasting in libp2p
    • We jump into method validate(PubSub, Message) in libp2p/protocols/pubsub/pubsub.nim
    • which was called by rpcHandler(GossipSub, PubSubPeer, RPCMsg)
  • a blockValidator message enqueues the validated object to the processing queue in block_processor
    • blockQueue: AsyncQueue[BlockEntry] (shared with request_manager and sync_manager)
    • This queue is then regularly processed to be made available to the consensus object pools.
  • a xyzValidator message adds the validated object to a pool in eth2_processor
    • Attestations (unaggregated and aggregated) get collected into batches.
    • Once a threshold is exceeded or after a timeout, they get validated together using BatchCrypto.

Security concerns

As the first line of defense in Nimbus, modules must be able to handle bursts of data that may come:

  • from malicious nodes trying to DOS us
  • from long periods of non-finality, creating lots of forks, attestations