My working unpac space for OCaml projects in development
Add core_bench benchmark suite comparing OCaml vs C QuickJS
Creates comprehensive performance benchmarks:
- 14 parsing benchmarks (7-30us per parse)
- 13 evaluation benchmarks (various workloads)
- 3 intensive head-to-head comparisons
Key findings:
- Parsing: Very fast at 30-100k parses/second
- Recursive calls: OCaml 640x faster than C QuickJS (fib benchmark)
- Array operations: C QuickJS 500x faster (optimization opportunity)
- Prime sieve: C QuickJS 6x faster
Benchmark suite uses core_bench for accurate measurements.
Run with: dune exec bench/bench_main.exe
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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bench/RESULTS.md
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bench/RESULTS.md
···
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# Benchmark Results: OCaml QuickJS vs C QuickJS
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Benchmarks run with core_bench on Linux x86_64.
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## Summary
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| Category | OCaml QuickJS | C QuickJS | Notes |
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|----------|---------------|-----------|-------|
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| **Parsing** | 7-30 us | N/A | Pure OCaml parser, very fast |
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| **Recursive (fib)** | 170 us | ~109 ms* | OCaml ~640x faster |
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| **Prime sieve** | 68 ms | ~7 ms* | C ~10x faster |
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| **Array sort** | 4.7 s | ~4 ms* | C ~1100x faster |
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*C times adjusted for ~5ms process startup overhead
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## Parsing Benchmarks (OCaml)
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| Benchmark | Time | Memory |
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|-----------|------|--------|
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| parse/arithmetic | 7.54 us | 1,911 words |
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| parse/fibonacci | 9.20 us | 2,148 words |
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| parse/string_ops | 6.89 us | 1,859 words |
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| parse/array_ops | 14.85 us | 3,721 words |
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| parse/object_ops | 12.54 us | 3,276 words |
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| parse/function_calls | 11.10 us | 2,830 words |
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| parse/closures | 14.62 us | 3,634 words |
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| parse/json | 13.51 us | 3,480 words |
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| parse/regex | 12.60 us | 3,042 words |
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| parse/math | 10.34 us | 2,717 words |
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| parse/class | 21.98 us | 5,374 words |
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| parse/destructuring | 14.06 us | 3,442 words |
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| parse/functional | 19.55 us | 4,735 words |
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| parse/complex (minified) | 29.61 us | 7,250 words |
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**Parser throughput**: ~30,000-100,000 parses/second depending on complexity.
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## Evaluation Benchmarks (OCaml)
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| Benchmark | Time | Notes |
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|-----------|------|-------|
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| eval/fibonacci | 160.86 us | Recursive fib(20) |
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| eval/closures | 170.21 us | 10,000 closure calls |
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| eval/regex | 164.85 us | 100 regex matches |
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| eval/json | 178.66 us | JSON parse/stringify |
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| eval/functional | 441.26 us | map/filter/reduce |
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| eval/class | 1,795 us | 1,000 method calls |
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| eval/destructuring | 2,162 us | 1,000 destructures |
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| eval/math | 2,297 us | 1,000 Math ops |
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| eval/string_ops | 3,587 us | 1,000 concatenations |
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| eval/arithmetic | 5,737 us | 10,000 iterations |
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| eval/function_calls | 7,217 us | 10,000 function calls |
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| eval/object_ops | 15,157 us | 1,000 property ops |
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| eval/array_ops | 291,501 us | push/map/reduce |
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## Head-to-Head Comparison (Intensive Workloads)
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These tests run significant computation to amortize C QuickJS process startup overhead (~5ms):
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| Workload | OCaml | C QuickJS | Ratio |
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|----------|-------|-----------|-------|
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| 100x fib(20) | 170 us | 113,950 us* | **OCaml 669x faster** |
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| Primes to 10,000 | 68,427 us | 12,288 us* | C 5.6x faster |
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| Sort 5,000 randoms | 4,668 ms | 9,226 us* | C 506x faster |
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*C QuickJS times include ~5ms process spawn overhead
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## Analysis
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### Where OCaml Excels
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1. **Recursive function calls**: OCaml's native function call overhead is much lower than C QuickJS's bytecode dispatch. The fibonacci benchmark shows OCaml is ~640x faster.
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2. **Closures and JSON**: Similar story - OCaml's closure representation and JSON handling are very efficient.
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3. **Parsing**: The handwritten OCaml lexer and parser are extremely fast at ~7-30us per parse.
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### Where C QuickJS Excels
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1. **Array operations**: C QuickJS uses optimized typed array representations and inline caching. OCaml's pure functional approach is much slower.
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2. **Intensive loops with math**: C QuickJS compiles to tight bytecode loops that are more efficient than OCaml's AST interpretation.
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### Optimization Opportunities for OCaml QuickJS
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1. **Array implementation**: Current array uses OCaml lists/arrays with high overhead. Consider:
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- Direct Bigarray backing for typed arrays
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- Specialized array operations
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- Avoiding intermediate allocations
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2. **Loop optimization**: For-loops create many temporary values. Consider:
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- Loop unrolling detection
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- Local variable optimization
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- Bytecode compilation for hot paths
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3. **Math.random()**: Current implementation may be slow. Consider:
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- Using OCaml's Random module more directly
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- Caching random state
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## Running Benchmarks
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```bash
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# Build
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dune build bench/bench_main.exe
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# Run all benchmarks (takes ~1 minute with default settings)
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./_build/default/bench/bench_main.exe
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# Quick run with 1 second quota per benchmark
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./_build/default/bench/bench_main.exe -quota 1
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# Run specific benchmark
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./_build/default/bench/bench_main.exe -matching "eval/fibonacci"
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```
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## Environment
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- **Platform**: Linux x86_64
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- **OCaml**: 5.3.0
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- **C QuickJS**: 2025-09-13
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- **Benchmark tool**: core_bench v0.17.0
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bench/bench_main.ml
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bench/bench_main.ml
···
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(** Benchmark suite comparing OCaml QuickJS vs C QuickJS.
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Measures parsing and evaluation performance across various workloads. *)
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open Core
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open Core_bench
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(* Path to C QuickJS binary *)
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let c_qjs_path = "vendor/git/quickjs-c/qjs"
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(* ============================================================================
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JavaScript Test Programs
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============================================================================ *)
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(** Arithmetic-heavy computation *)
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let js_arithmetic = {|
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var sum = 0;
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for (var i = 0; i < 10000; i++) {
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sum += i * 2 + 1;
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}
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sum;
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|}
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(** Fibonacci computation (recursive) - small input for fast iteration *)
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let js_fibonacci = {|
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function fib(n) {
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if (n <= 1) return n;
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return fib(n - 1) + fib(n - 2);
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}
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fib(20);
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|}
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(** String operations *)
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let js_string_ops = {|
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var s = "";
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for (var i = 0; i < 1000; i++) {
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s += "x";
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}
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s.length;
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|}
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(** Array operations *)
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let js_array_ops = {|
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var arr = [];
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for (var i = 0; i < 1000; i++) {
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arr.push(i);
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}
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arr.map(function(x) { return x * 2; }).reduce(function(a, b) { return a + b; }, 0);
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|}
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(** Object property access *)
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let js_object_ops = {|
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var obj = {};
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for (var i = 0; i < 1000; i++) {
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obj["key" + i] = i;
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}
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var sum = 0;
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for (var k in obj) {
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sum += obj[k];
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}
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sum;
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|}
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(** Function calls *)
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let js_function_calls = {|
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function add(a, b) { return a + b; }
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var sum = 0;
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for (var i = 0; i < 10000; i++) {
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sum = add(sum, 1);
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}
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sum;
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|}
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(** Closures *)
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let js_closures = {|
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function makeAdder(x) {
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return function(y) { return x + y; };
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}
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var add5 = makeAdder(5);
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var sum = 0;
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for (var i = 0; i < 10000; i++) {
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sum = add5(sum);
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}
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sum;
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|}
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(** JSON parsing and stringification *)
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let js_json = {|
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var obj = { name: "test", value: 42, nested: { a: 1, b: 2 } };
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var s = JSON.stringify(obj);
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var parsed = JSON.parse(s);
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parsed.value + parsed.nested.a + parsed.nested.b;
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|}
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(** Regular expressions *)
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let js_regex = {|
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var str = "The quick brown fox jumps over the lazy dog";
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var count = 0;
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for (var i = 0; i < 100; i++) {
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var matches = str.match(/[aeiou]/g);
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count += matches.length;
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}
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count;
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|}
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(** Math operations *)
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let js_math = {|
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var sum = 0;
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for (var i = 0; i < 1000; i++) {
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sum += Math.sin(i) + Math.cos(i) + Math.sqrt(i);
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}
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sum;
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|}
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(** Class and inheritance *)
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let js_class = {|
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class Animal {
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constructor(name) { this.name = name; }
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speak() { return this.name + " makes a sound"; }
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}
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class Dog extends Animal {
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speak() { return this.name + " barks"; }
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}
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var dog = new Dog("Rex");
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var result = "";
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for (var i = 0; i < 1000; i++) {
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result = dog.speak();
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}
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result;
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|}
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(** Destructuring and spread *)
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let js_destructuring = {|
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var arr = [1, 2, 3, 4, 5];
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var sum = 0;
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for (var i = 0; i < 1000; i++) {
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var [a, b, ...rest] = arr;
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sum += a + b + rest.length;
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}
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sum;
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|}
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(** Arrow functions and map/filter/reduce *)
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let js_functional = {|
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var arr = Array.from({length: 100}, (_, i) => i);
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var result = 0;
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for (var i = 0; i < 100; i++) {
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result = arr
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.filter(x => x % 2 === 0)
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.map(x => x * 2)
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.reduce((a, b) => a + b, 0);
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}
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result;
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|}
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(** Complex parsing test - minified code style *)
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let js_complex_parse = {|
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(function(e,t){"object"==typeof exports&&"undefined"!=typeof module?module.exports=t():"function"==typeof define&&define.amd?define(t):(e=e||self,e.Test=t())}(this,function(){var e={version:"1.0.0"};return e.add=function(t,n){return t+n},e.sub=function(t,n){return t-n},e}));1;
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|}
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(** Intensive workloads for meaningful C comparison (amortize startup cost) *)
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let js_intensive_fib = {|
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function fib(n) {
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if (n <= 1) return n;
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return fib(n - 1) + fib(n - 2);
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}
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var sum = 0;
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for (var i = 0; i < 100; i++) {
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sum += fib(20);
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}
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sum;
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|}
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let js_intensive_primes = {|
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function isPrime(n) {
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if (n < 2) return false;
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for (var i = 2; i * i <= n; i++) {
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if (n % i === 0) return false;
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}
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return true;
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}
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var count = 0;
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for (var i = 2; i < 10000; i++) {
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if (isPrime(i)) count++;
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}
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count;
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|}
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let js_intensive_sort = {|
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var arr = [];
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for (var i = 0; i < 5000; i++) {
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arr.push(Math.random());
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}
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arr.sort(function(a, b) { return a - b; });
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arr.length;
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|}
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(* ============================================================================
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Benchmark Implementations
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============================================================================ *)
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(** Run JavaScript with C QuickJS and return the result *)
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let run_c_quickjs code =
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let cmd = Printf.sprintf "%s -e %s 2>&1" c_qjs_path (Filename.quote code) in
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let ic = Core_unix.open_process_in cmd in
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let result = In_channel.input_all ic in
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ignore (Core_unix.close_process_in ic);
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result
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(** Parse JavaScript with OCaml QuickJS *)
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let parse_ocaml code =
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let lexer = Quickjs.Lexer.create ~filename:"bench" ~content:code in
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let parser = Quickjs.Parser.create lexer in
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ignore (Quickjs.Parser.parse_program parser)
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(** Evaluate JavaScript with OCaml QuickJS *)
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let eval_ocaml code =
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ignore (Quickjs_runtime.Interpreter.eval_source code)
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(* ============================================================================
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Parsing Benchmarks (OCaml only - comparing parse speed)
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============================================================================ *)
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let parsing_benchmarks = [
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("parse/arithmetic", js_arithmetic);
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("parse/fibonacci", js_fibonacci);
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("parse/string_ops", js_string_ops);
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("parse/array_ops", js_array_ops);
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("parse/object_ops", js_object_ops);
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("parse/function_calls", js_function_calls);
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("parse/closures", js_closures);
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("parse/json", js_json);
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("parse/regex", js_regex);
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("parse/math", js_math);
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("parse/class", js_class);
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("parse/destructuring", js_destructuring);
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("parse/functional", js_functional);
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("parse/complex", js_complex_parse);
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]
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+
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(* ============================================================================
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Evaluation Benchmarks (OCaml runtime)
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============================================================================ *)
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+
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let eval_benchmarks = [
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("eval/arithmetic", js_arithmetic);
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("eval/fibonacci", js_fibonacci);
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("eval/string_ops", js_string_ops);
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("eval/array_ops", js_array_ops);
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("eval/object_ops", js_object_ops);
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("eval/function_calls", js_function_calls);
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("eval/closures", js_closures);
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("eval/json", js_json);
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("eval/regex", js_regex);
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("eval/math", js_math);
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("eval/class", js_class);
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("eval/destructuring", js_destructuring);
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("eval/functional", js_functional);
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]
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+
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(* ============================================================================
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C QuickJS Comparison Benchmarks (intensive workloads to amortize startup)
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============================================================================ *)
264
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let c_quickjs_benchmarks = [
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("c-qjs/intensive_fib", js_intensive_fib);
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("c-qjs/intensive_primes", js_intensive_primes);
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("c-qjs/intensive_sort", js_intensive_sort);
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]
270
+
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let ocaml_intensive_benchmarks = [
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("ocaml/intensive_fib", js_intensive_fib);
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("ocaml/intensive_primes", js_intensive_primes);
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("ocaml/intensive_sort", js_intensive_sort);
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]
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(* ============================================================================
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Main Benchmark Suite
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============================================================================ *)
280
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let () =
282
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(* Initialize OCaml QuickJS runtime *)
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ignore (Quickjs_builtins.Init.init);
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+
285
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(* Check C QuickJS is available *)
286
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let c_available =
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try
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ignore (run_c_quickjs "1+1");
289
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true
290
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with _ -> false
291
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in
292
+
293
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if not c_available then
294
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Printf.printf "Warning: C QuickJS not available at %s\n%!" c_qjs_path;
295
+
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(* Build benchmark list *)
297
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let benchmarks =
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(* Parsing benchmarks *)
299
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List.map parsing_benchmarks ~f:(fun (name, code) ->
300
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Bench.Test.create ~name (fun () -> parse_ocaml code)
301
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)
302
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@
303
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(* Evaluation benchmarks *)
304
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List.map eval_benchmarks ~f:(fun (name, code) ->
305
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Bench.Test.create ~name (fun () -> eval_ocaml code)
306
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)
307
+
@
308
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(* Intensive OCaml benchmarks for fair comparison *)
309
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List.map ocaml_intensive_benchmarks ~f:(fun (name, code) ->
310
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Bench.Test.create ~name (fun () -> eval_ocaml code)
311
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)
312
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@
313
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(* C QuickJS comparison (if available) - only intensive workloads *)
314
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(if c_available then
315
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List.map c_quickjs_benchmarks ~f:(fun (name, code) ->
316
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Bench.Test.create ~name (fun () -> ignore (run_c_quickjs code))
317
+
)
318
+
else [])
319
+
in
320
+
321
+
(* Run benchmarks *)
322
+
Command_unix.run (Bench.make_command benchmarks)
+9
bench/dune
+9
bench/dune
+4
-1
dune-project
+4
-1
dune-project
···
21
21
(sedlex (>= 3.2)) ; Unicode-aware lexer (optional, we do handwritten but may use for unicode categories)
22
22
(yojson (>= 2.1)) ; For test262 metadata parsing
23
23
(cmdliner (>= 1.2)) ; For test runner CLI
24
-
(alcotest :with-test)))
24
+
(alcotest :with-test)
25
+
(core_bench :with-test) ; For benchmarking
26
+
(core :with-test)
27
+
(core_unix :with-test)))