highperfocused/bitcoin
1
0
Fork 0
mirror of https://github.com/bitcoin/bitcoin.git synced 2026-01-20 23:29:12 +01:00
Code Issues Packages Projects Releases Wiki Activity

optimization: bulk serialization reads in UndoRead, ReadBlock

Browse Source 
The obfuscation (XOR) operations are currently done byte-by-byte during serialization. Buffering the reads will enable batching the obfuscation operations later.

Different operating systems handle file caching differently, so reading larger batches (and processing them from memory) is measurably faster, likely because of fewer native fread calls and reduced lock contention.

Note that `ReadRawBlock` doesn't need buffering since it already reads the whole block directly.
Unlike `ReadBlockUndo`, the new `ReadBlock` implementation delegates to `ReadRawBlock`, which uses more memory than a buffered alternative but results in slightly simpler code and a small performance increase (~0.4%). This approach also clearly documents that `ReadRawBlock` is a logical subset of `ReadBlock` functionality.

The current implementation, which iterates over a fixed-size buffer, provides a more general alternative to Cory Fields' solution of reading the entire block size in advance.

Buffer sizes were selected based on benchmarking to ensure the buffered reader produces performance similar to reading the whole block into memory. Smaller buffers were slower, while larger ones showed diminishing returns.

------

> macOS Sequoia 15.3.1
> C++ compiler .......................... Clang 19.1.7
> cmake -B build -DBUILD_BENCH=ON -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ && cmake --build build -j$(nproc) && build/bin/bench_bitcoin -filter='ReadBlockBench' -min-time=10000

Before:

|               ns/op |                op/s |    err% |     total | benchmark
|--------------------:|--------------------:|--------:|----------:|:----------
|        2,271,441.67 |              440.25 |    0.1% |     11.00 | `ReadBlockBench`

After:

|               ns/op |                op/s |    err% |     total | benchmark
|--------------------:|--------------------:|--------:|----------:|:----------
|        1,738,971.29 |              575.05 |    0.2% |     10.97 | `ReadBlockBench`

------

> Ubuntu 24.04.2 LTS
> C++ compiler .......................... GNU 13.3.0
> cmake -B build -DBUILD_BENCH=ON -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ && cmake --build build -j$(nproc) && build/bin/bench_bitcoin -filter='ReadBlockBench' -min-time=20000

Before:

|               ns/op |                op/s |    err% |          ins/op |          cyc/op |    IPC |         bra/op |   miss% |     total | benchmark
|--------------------:|--------------------:|--------:|----------------:|----------------:|-------:|---------------:|--------:|----------:|:----------
|        6,895,987.11 |              145.01 |    0.0% |   71,055,269.86 |   23,977,374.37 |  2.963 |   5,074,828.78 |    0.4% |     22.00 | `ReadBlockBench`

After:

|               ns/op |                op/s |    err% |          ins/op |          cyc/op |    IPC |         bra/op |   miss% |     total | benchmark
|--------------------:|--------------------:|--------:|----------------:|----------------:|-------:|---------------:|--------:|----------:|:----------
|        5,771,882.71 |              173.25 |    0.0% |   65,741,889.82 |   20,453,232.33 |  3.214 |   3,971,321.75 |    0.3% |     22.01 | `ReadBlockBench`

Co-authored-by: maflcko <6399679+maflcko@users.noreply.github.com>
Co-authored-by: Ryan Ofsky <ryan@ofsky.org>
Co-authored-by: Martin Leitner-Ankerl <martin.ankerl@gmail.com>
Co-authored-by: Cory Fields <cory-nospam-@coryfields.com>
This commit is contained in:
Lőrinc
2025-03-26 12:52:29 +01:00
parent 056cb3c0d2
commit 520965e293
3 changed files with 105 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
src/node/blockstorage.cpp
View File

@@ -660,11 +660,12 @@ bool BlockManager::ReadBlockUndo(CBlockUndo& blockundo, const CBlockIndex& index
const FlatFilePos pos{WITH_LOCK(::cs_main, return index.GetUndoPos())};
// Open history file to read
AutoFile filein{OpenUndoFile(pos, true)};
if (filein.IsNull()) {
AutoFile file{OpenUndoFile(pos, true)};
if (file.IsNull()) {
LogError("OpenUndoFile failed for %s while reading block undo", pos.ToString());
return false;
}
BufferedReader filein{std::move(file)};
try {
// Read block
@@ -996,15 +997,14 @@ bool BlockManager::ReadBlock(CBlock& block, const FlatFilePos& pos) const
block.SetNull();
// Open history file to read
AutoFile filein{OpenBlockFile(pos, /*fReadOnly=*/true)};
if (filein.IsNull()) {
LogError("OpenBlockFile failed for %s while reading block", pos.ToString());
std::vector<uint8_t> block_data;
if (!ReadRawBlock(block_data, pos)) {
return false;
}
try {
// Read block
filein >> TX_WITH_WITNESS(block);
SpanReader{block_data} >> TX_WITH_WITNESS(block);
} catch (const std::exception& e) {
LogError("Deserialize or I/O error - %s at %s while reading block", e.what(), pos.ToString());
return false;