perf: use tiny cache for best chainlock in CbTx instead running heavy ReadBlockFromDisk

src/chainparams.cpp

@@ -921,6 +921,7 @@ class CRegTestParams : public CChainParams {
         UpdateLLMQTestParametersFromArgs(args, Consensus::LLMQType::LLMQ_TEST_INSTANTSEND);
         UpdateLLMQTestParametersFromArgs(args, Consensus::LLMQType::LLMQ_TEST_PLATFORM);
         UpdateLLMQInstantSendDIP0024FromArgs(args);
+        assert(consensus.V20Height >= consensus.DIP0003Height);
     }
 
     /**

src/evo/cbtx.cpp

@@ -331,13 +331,26 @@ bool CheckCbTxBestChainlock(const CBlock& block, const CBlockIndex* pindex,
         return true;
     }
 
+    static Mutex cached_mutex;
+    static const CBlockIndex* cached_pindex GUARDED_BY(cached_mutex){nullptr};
+    static std::optional<std::pair<CBLSSignature, uint32_t>> cached_chainlock GUARDED_BY(cached_mutex){std::nullopt};
+
     auto best_clsig = chainlock_handler.GetBestChainLock();
     if (best_clsig.getHeight() == pindex->nHeight - 1 && cbTx.bestCLHeightDiff == 0 && cbTx.bestCLSignature == best_clsig.getSig()) {
         // matches our best clsig which still hold values for the previous block
+        LOCK(cached_mutex);
+        cached_chainlock = std::make_pair(cbTx.bestCLSignature, cbTx.bestCLHeightDiff);
+        cached_pindex = pindex;
         return true;
     }
 
-    const auto prevBlockCoinbaseChainlock = GetNonNullCoinbaseChainlock(pindex->pprev);
+    std::optional<std::pair<CBLSSignature, uint32_t>> prevBlockCoinbaseChainlock{std::nullopt};
+    if (LOCK(cached_mutex); cached_pindex == pindex->pprev) {
+        prevBlockCoinbaseChainlock = cached_chainlock;
+    }
+    if (!prevBlockCoinbaseChainlock.has_value()) {
+        prevBlockCoinbaseChainlock = GetNonNullCoinbaseChainlock(pindex->pprev);
+    }
     // If std::optional prevBlockCoinbaseChainlock is empty, then up to the previous block, coinbase Chainlock is null.
     if (prevBlockCoinbaseChainlock.has_value()) {
         // Previous block Coinbase has a non-null Chainlock: current block's Chainlock must be non-null and at least as new as the previous one
@@ -355,12 +368,18 @@ bool CheckCbTxBestChainlock(const CBlock& block, const CBlockIndex* pindex,
         int curBlockCoinbaseCLHeight = pindex->nHeight - static_cast<int>(cbTx.bestCLHeightDiff) - 1;
         if (best_clsig.getHeight() == curBlockCoinbaseCLHeight && best_clsig.getSig() == cbTx.bestCLSignature) {
             // matches our best (but outdated) clsig, no need to verify it again
+            LOCK(cached_mutex);
+            cached_chainlock = std::make_pair(cbTx.bestCLSignature, cbTx.bestCLHeightDiff);
+            cached_pindex = pindex;
             return true;
         }
         uint256 curBlockCoinbaseCLBlockHash = pindex->GetAncestor(curBlockCoinbaseCLHeight)->GetBlockHash();
         if (chainlock_handler.VerifyChainLock(llmq::CChainLockSig(curBlockCoinbaseCLHeight, curBlockCoinbaseCLBlockHash, cbTx.bestCLSignature)) != llmq::VerifyRecSigStatus::Valid) {
             return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-cbtx-invalid-clsig");
         }
+        LOCK(cached_mutex);
+        cached_chainlock = std::make_pair(cbTx.bestCLSignature, cbTx.bestCLHeightDiff);
+        cached_pindex = pindex;
     } else if (cbTx.bestCLHeightDiff != 0) {
         // Null bestCLSignature is allowed only with bestCLHeightDiff = 0
         return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-cbtx-cldiff");
@@ -437,8 +456,8 @@ std::optional<std::pair<CBLSSignature, uint32_t>> GetNonNullCoinbaseChainlock(co
         return std::nullopt;
     }
 
-    // There's no CbTx before DIP0003 activation
-    if (!DeploymentActiveAt(*pindex, Params().GetConsensus(), Consensus::DEPLOYMENT_DIP0003)) {
+    // There's no CL in CbTx before v20 activation
+    if (!DeploymentActiveAt(*pindex, Params().GetConsensus(), Consensus::DEPLOYMENT_V20)) {
         return std::nullopt;
     }
 
@@ -454,14 +473,9 @@ std::optional<std::pair<CBLSSignature, uint32_t>> GetNonNullCoinbaseChainlock(co
         return std::nullopt;
     }
 
-    const CCbTx& cbtx = opt_cbtx.value();
-    if (cbtx.nVersion < CCbTx::Version::CLSIG_AND_BALANCE) {
-        return std::nullopt;
-    }
-
-    if (!cbtx.bestCLSignature.IsValid()) {
+    if (!opt_cbtx->bestCLSignature.IsValid()) {
         return std::nullopt;
     }
 
-    return std::make_pair(cbtx.bestCLSignature, cbtx.bestCLHeightDiff);
+    return std::make_pair(opt_cbtx->bestCLSignature, opt_cbtx->bestCLHeightDiff);
 }

test/functional/feature_assumevalid.py

@@ -62,7 +62,7 @@ class AssumeValidTest(BitcoinTestFramework):
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 3
-        self.extra_args = ["-dip3params=9000:9000", "-checkblockindex=0"]
+        self.extra_args = ["-dip3params=9000:9000", '-testactivationheight=v20@9000', "-checkblockindex=0"]
         self.rpc_timeout = 120
 
     def setup_network(self):

test/functional/feature_csv_activation.py

@@ -100,6 +100,7 @@ def set_test_params(self):
             '-peertimeout=999999',  # bump because mocktime might cause a disconnect otherwise
             '-whitelist=noban@127.0.0.1',
             '-dip3params=2000:2000',
+            '-testactivationheight=v20@2000',
             f'-testactivationheight=csv@{CSV_ACTIVATION_HEIGHT}',
             '-par=1',  # Use only one script thread to get the exact reject reason for testing
         ]]