perf: add in quorumBaseBlockIndexCache to reduce cs_main contention #6422
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but it doesn't change observable behavior? maybe more of a |
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It does change internal logic a bit though. |
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As expected; after testnet testing, contention over cs_main related to this line went from 20% -> 0% On rc.1 cs_main contention represents ~30% of contention (although I previously observed it at ~40%), using this PR, cs_main contention was only ~18% of total contention. Still about 10% of this 18% is related to llmq/quorums, so should try to cache the chain tip as well. But this PR appears to be producing the expected results. |
| @@ -252,6 +252,10 @@ class CQuorumManager | |||
| mutable Mutex cs_cleanup; | |||
| mutable std::map<Consensus::LLMQType, unordered_lru_cache<uint256, uint256, StaticSaltedHasher>> cleanupQuorumsCache GUARDED_BY(cs_cleanup); | |||
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| mutable Mutex cs_quorumBaseBlockIndexCache; | |||
| // On mainnet, we have around 62 quorums active at any point; let's cache a little more than double that to be safe. | |||
| mutable unordered_lru_cache<uint256 /*quorum_hash*/, const CBlockIndex* /*pindex*/, StaticSaltedHasher, 128 /*max_size*/> quorumBaseBlockIndexCache; | |||
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nit: accordingly code-style, members should start for m_
Class member variables have a m_ prefix.
https://github.com/dashpay/dash/blob/master/doc/developer-notes.md?plain=1#L88-L90
| mutable unordered_lru_cache<uint256 /*quorum_hash*/, const CBlockIndex* /*pindex*/, StaticSaltedHasher, 128 /*max_size*/> quorumBaseBlockIndexCache; | |
| mutable unordered_lru_cache<uint256 /*quorum_hash*/, const CBlockIndex* /*pindex*/, StaticSaltedHasher, 128 /*max_size*/> m_baseblock_index_cache; |
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Yeah; we should probably do a refactor for whole dash headers like this and rename. Thoughts?
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for whole dash headers
I would not do it. Adding new one - add them in new style. Renaming all old one just for sack of renaming doesn't worth IMO. But in case of any refactoring around it is a good cause to do it.
For example, bitcoin does it everytime when code is refactored, for example bitcoin#21148 - created new class, moved data there and all members got proper nice names such as "mapOrphanTransactionsByPrev" -> "m_outpoint_to_orphan_it"
Issue being fixed or feature implemented
subset of #6418; only includes the new quorumBaseBlockIndexCache, doesn't include the caching of the chain-tip, as that introduced regressions I'm still debugging.
What was done?
introduce a LRU cache for quorumHash -> const CBlockIndex*; this should significantly reduce cs_main contention during high transaction load.
How Has This Been Tested?
Ran tests locally; let's see CI happy, and I also intend to run this on a testnet MN first and see the level of contention reduction
Breaking Changes
None
Checklist:
Go over all the following points, and put an
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