Inside Bitcoin

1// Copyright (c) 2022-present The Bitcoin Core developers
2// Distributed under the MIT software license, see the accompanying
3// file COPYING or https://www.opensource.org/licenses/mit-license.php.
4
5#include <bench/bench.h>
6#include <bench/data/block413567.raw.h>
7#include <chainparams.h>
8#include <flatfile.h>
9#include <node/blockstorage.h>
10#include <streams.h>
11#include <test/util/setup_common.h>
12#include <uint256.h>
13#include <util/fs.h>
14#include <validation.h>
15
16#include <cstdint>
17#include <cstdio>
18#include <map>
19#include <memory>
20#include <span>
21#include <stdexcept>
22
23/**
24 * The LoadExternalBlockFile() function is used during -reindex and -loadblock.
25 *
26 * Create a test file that's similar to a datadir/blocks/blk?????.dat file,
27 * It contains around 134 copies of the same block (typical size of real block files).
28 * For each block in the file, LoadExternalBlockFile() won't find its parent,
29 * and so will skip the block. (In the real system, it will re-read the block
30 * from disk later when it encounters its parent.)
31 *
32 * This benchmark measures the performance of deserializing the block (or just
33 * its header, beginning with PR 16981).
34 */
35static void LoadExternalBlockFile(benchmark::Bench& bench)
36{
37    const auto testing_setup{MakeNoLogFileContext<const TestingSetup>(ChainType::MAIN)};
38
39    // Create a single block as in the blocks files (magic bytes, block size,
40    // block data) as a stream object.
41    const fs::path blkfile{testing_setup.get()->m_path_root / "blk.dat"};
42    DataStream ss{};
43    auto params{testing_setup->m_node.chainman->GetParams()};
44    ss << params.MessageStart();
45    ss << static_cast<uint32_t>(benchmark::data::block413567.size());
46    // Use span-serialization to avoid writing the size first.
47    ss << std::span{benchmark::data::block413567};
48
49    // Create the test file.
50    {
51        // "wb+" is "binary, O_RDWR | O_CREAT | O_TRUNC".
52        FILE* file{fsbridge::fopen(blkfile, "wb+")};
53        // Make the test block file about 128 MB in length.
54        for (size_t i = 0; i < node::MAX_BLOCKFILE_SIZE / ss.size(); ++i) {
55            if (fwrite(ss.data(), 1, ss.size(), file) != ss.size()) {
56                throw std::runtime_error("write to test file failed\n");
57            }
58        }
59        fclose(file);
60    }
61
62    std::multimap<uint256, FlatFilePos> blocks_with_unknown_parent;
63    FlatFilePos pos;
64    bench.setup([&] {
65            blocks_with_unknown_parent.clear();
66            pos = FlatFilePos{};
67        })
68        .run([&] {
69            // "rb" is "binary, O_RDONLY", positioned to the start of the file.
70            // The file will be closed by LoadExternalBlockFile().
71            AutoFile file{fsbridge::fopen(blkfile, "rb")};
72            testing_setup->m_node.chainman->LoadExternalBlockFile(file, &pos, &blocks_with_unknown_parent);
73        });
74    fs::remove(blkfile);
75}
76
77BENCHMARK(LoadExternalBlockFile);
78