mirror of
https://github.com/simdjson/simdjson
synced 2026-06-08 17:27:07 +00:00
Francisco Geiman Thiesen
58c92d6d82
* Adding compile time json path * using string_view * Adding support for compile-time json pointer as well. * Removing unnecessary comment * Tests now working, still will re-review. * Adding documentation on the compile-time json path/pointer parsing feature. * Adding benchmark showing the significant performance advantage of using compiled paths whenever you have them a priori. * going for JSONPath (correct wording). * minor update (mostly doc) --------- Co-authored-by: Daniel Lemire <daniel@lemire.me>
47 lines
1.4 KiB
Markdown
47 lines
1.4 KiB
Markdown
# Accessor Performance Benchmarks (C++26)
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These benchmarks compare the performance of runtime vs compile-time JSON accessors.
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For the comparison to be meaningful, you must build simdjson with support for
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C++26 reflexion. See the `p2996` repository in the main project directory.
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## Files
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- `accessor_benchmark.h` - Common benchmark framework and test data
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- `runtime_accessors.h` - Runtime `at_path()` benchmarks
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- `compile_time_accessors.h` - Compile-time `at_path_compiled()` benchmarks (requires C++26 reflection)
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## Benchmarks
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Each benchmark measures parsing + single field access:
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1. **accessor_simple** - Simple field: `.name`
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2. **accessor_nested** - Nested field: `.address.city`
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3. **accessor_deep** - Deep nested field: `.address.coordinates.lat`
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## Building (Linux/macOS)
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```bash
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cmake -B build -D SIMDJSON_STATIC_REFLECTION=ON -DSIMDJSON_DEVELOPER_MODE=ON
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cmake --build build --target=bench_ondemand
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```
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The `SIMDJSON_STATIC_REFLECTION` will be made unnecessary once mainstream compilers
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begin supporting C++26 sufficiently well.
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## Running (Linux/macOS)
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```bash
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# Run all accessor benchmarks
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./build/bench_ondemand --benchmark_filter="accessor"
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```
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## Results
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We find that compile-time accessors show performance improvements that scale with path depth:
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- Simple fields: ~1.2x faster
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- Nested fields: ~1.5x faster
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- Deep nested fields: ~1.8x faster
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The speedup comes from eliminating runtime path parsing and conversion overhead.
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