bench: Add block assemble benchmark

src/Makefile.bench.include

@@ -15,6 +15,7 @@ bench_bench_bitcoin_SOURCES = \
   bench/bench_bitcoin.cpp \
   bench/bench.cpp \
   bench/bench.h \
+  bench/block_assemble.cpp \
   bench/checkblock.cpp \
   bench/checkqueue.cpp \
   bench/Examples.cpp \

src/bench/block_assemble.cpp

@@ -0,0 +1,115 @@
+// Copyright (c) 2011-2017 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <bench/bench.h>
+#include <chainparams.h>
+#include <coins.h>
+#include <consensus/merkle.h>
+#include <consensus/validation.h>
+#include <miner.h>
+#include <policy/policy.h>
+#include <scheduler.h>
+#include <txdb.h>
+#include <txmempool.h>
+#include <utiltime.h>
+#include <validation.h>
+#include <validationinterface.h>
+
+#include <boost/thread.hpp>
+
+#include <list>
+#include <vector>
+
+static std::shared_ptr<CBlock> PrepareBlock(const CScript& coinbase_scriptPubKey)
+{
+    auto block = std::make_shared<CBlock>(
+        BlockAssembler{Params()}
+            .CreateNewBlock(coinbase_scriptPubKey, /* fMineWitnessTx */ true)
+            ->block);
+
+    block->nTime = ::chainActive.Tip()->GetMedianTimePast() + 1;
+    block->hashMerkleRoot = BlockMerkleRoot(*block);
+
+    return block;
+}
+
+
+static CTxIn MineBlock(const CScript& coinbase_scriptPubKey)
+{
+    auto block = PrepareBlock(coinbase_scriptPubKey);
+
+    while (!CheckProofOfWork(block->GetHash(), block->nBits, Params().GetConsensus())) {
+        assert(++block->nNonce);
+    }
+
+    bool processed{ProcessNewBlock(Params(), block, true, nullptr)};
+    assert(processed);
+
+    return CTxIn{block->vtx[0]->GetHash(), 0};
+}
+
+
+static void AssembleBlock(benchmark::State& state)
+{
+    const std::vector<unsigned char> op_true{OP_TRUE};
+    CScriptWitness witness;
+    witness.stack.push_back(op_true);
+
+    uint256 witness_program;
+    CSHA256().Write(&op_true[0], op_true.size()).Finalize(witness_program.begin());
+
+    const CScript SCRIPT_PUB{CScript(OP_0) << std::vector<unsigned char>{witness_program.begin(), witness_program.end()}};
+
+    // Switch to regtest so we can mine faster
+    // Also segwit is active, so we can include witness transactions
+    SelectParams(CBaseChainParams::REGTEST);
+
+    InitScriptExecutionCache();
+
+    boost::thread_group thread_group;
+    CScheduler scheduler;
+    {
+        ::pblocktree.reset(new CBlockTreeDB(1 << 20, true));
+        ::pcoinsdbview.reset(new CCoinsViewDB(1 << 23, true));
+        ::pcoinsTip.reset(new CCoinsViewCache(pcoinsdbview.get()));
+
+        const CChainParams& chainparams = Params();
+        thread_group.create_thread(boost::bind(&CScheduler::serviceQueue, &scheduler));
+        GetMainSignals().RegisterBackgroundSignalScheduler(scheduler);
+        LoadGenesisBlock(chainparams);
+        CValidationState state;
+        ActivateBestChain(state, chainparams);
+        assert(::chainActive.Tip() != nullptr);
+        const bool witness_enabled{IsWitnessEnabled(::chainActive.Tip(), chainparams.GetConsensus())};
+        assert(witness_enabled);
+    }
+
+    // Collect some loose transactions that spend the coinbases of our mined blocks
+    constexpr size_t NUM_BLOCKS{200};
+    std::array<CTransactionRef, NUM_BLOCKS - COINBASE_MATURITY + 1> txs;
+    for (size_t b{0}; b < NUM_BLOCKS; ++b) {
+        CMutableTransaction tx;
+        tx.vin.push_back(MineBlock(SCRIPT_PUB));
+        tx.vin.back().scriptWitness = witness;
+        tx.vout.emplace_back(1337, SCRIPT_PUB);
+        if (NUM_BLOCKS - b >= COINBASE_MATURITY)
+            txs.at(b) = MakeTransactionRef(tx);
+    }
+    for (const auto& txr : txs) {
+        CValidationState state;
+        bool ret{::AcceptToMemoryPool(::mempool, state, txr, nullptr /* pfMissingInputs */, nullptr /* plTxnReplaced */, false /* bypass_limits */, /* nAbsurdFee */ 0)};
+        assert(ret);
+    }
+
+    while (state.KeepRunning()) {
+        PrepareBlock(SCRIPT_PUB);
+    }
+
+    thread_group.interrupt_all();
+    thread_group.join_all();
+    GetMainSignals().FlushBackgroundCallbacks();
+    GetMainSignals().UnregisterBackgroundSignalScheduler();
+}
+
+BENCHMARK(AssembleBlock, 700);