kama benchmark results

Generated: 2026-09-21 13:07 · arch: aarch64 (Linux) · in the kama-bench container

Toolchains: clang Ubuntu clang version 18.1.3 (1ubuntu1) · rustc 1.79.0 (129f3b996 2024-06-10) · go version go1.22.5 linux/arm64 · dotnet 8.0.422 · openjdk version "21.0.11" 2026-04-21 · node v22.16.0 · Lua 5.4.6 Copyright (C) 1994-2023 Lua.org, PUC-Rio · Python 3.12.3 Timing: hyperfine --warmup 2 --runs 8 --shell=none (median); the (N×) after each time is relative to kama for that workload (native → kama, wasm → kama→wasm). Peak RSS: /usr/bin/time -v.

How to read this (please read before drawing conclusions)#

kama transpiles to C and is compiled by the same clang as the C baseline, so on native compute workloads kama is expected to be within measurement noise of C/C++ — that is the design, not a finding. All four LLVM-AOT languages (C, C++, Rust, kama) are compiled at -O3 for an apples-to-apples comparison — otherwise the optimization level, not the language, dominates a tiny kernel (e.g. fib at C--O2 vs Rust--O3 differs ~20%, but at equal -O3 C and Rust are identical). The signals worth trusting here are:

1. kama (native) vs managed/interpreted languages (C#, Java, Go, Lua, Python),
2. peak RSS, compile time, and package size (the low-footprint / self-contained goal),
3. on the WASM track, kama→wasm vs hand-written JS/TS under the same node.

Methodology — pre-sizing: in map, every language whose standard map has a capacity API pre-sizes it for the keys it will insert (kama Map.withCapacity, C++ reserve, Rust with_capacity, Go make(m, n), C# and Java constructor capacity). Lua, Python and JS have no such API for their built-in table/dict/Map, so they grow from small — the one asymmetry left in that row.

Methodology — run isolated: these are short workloads, so parallel load badly skews them — run the bench with nothing else competing for CPU/IO. (The /work bind mount, virtiofs/9p on macOS/Windows, adds only ~0.3–1.7 ms for native and wasm under a controlled idle measurement — negligible — so artifacts are measured in place.)

WASM is run under node --no-liftoff. V8 compiles wasm in two tiers — Liftoff (baseline: fast to compile, slow to run) then TurboFan (optimizing). For these tiny single-shot processes V8 often never tiers up before exit (worse under load), so default node measured Liftoff wasm — ~4× slower and wildly variable (σ up to 9.8 ms), while JS always got its optimizing JIT. --no-liftoff forces TurboFan, giving optimized, stable wasm (σ ~0.3 ms) — what a real long-running app gets (its hot loops tier up on their own) and a fair compare vs V8's auto-JIT'd JS. Strict IEEE throughout (no -ffast-math).

The compute workloads (fib/pi/collatz) are tuned so the slow interpreters finish quickly; the fast compiled languages run in a few ms, so small absolute differences between them are noise — except dispatch, which measures true dynamic dispatch (see Workloads): the AOT cluster (kama/C/C++/Rust) converges there, while Go's interface dispatch trails ~2×.

Two of these rows measure different things and are named accordingly. map_kernel pins the algorithm, hash, and capacity across every language — a pure codegen number, where the AOT cluster should converge. map lets each language use its idiomatic map — a library-design number, where they legitimately should not. Read the first for "is kama as fast as C?", the second for "how good is the shipped container?". C appears only in map_kernel: it has no stdlib hashmap to enter in map.

The alloc workload is the one to watch for the no-GC story: it churns ~2M growable-list appends and 2000 collection lifetimes, so it contrasts kama's deterministic RAII free against the garbage collectors (Go, C#, Java, Lua, Python, JS) and against the RAII peers (C++ vector, Rust Vec). Watch its peak RSS in particular — GC runtimes keep dead allocations resident until a collection runs.

Fairness gate (checksum equality)#

Every language must produce the same exit-code checksum as kama per workload, or the algorithms have diverged:

• fib: checksum = 225 (exit code) — ✓ all match
• pi: checksum = 27 (exit code) — ✓ all match
• collatz: checksum = 2 (exit code) — ✓ all match
• dispatch: checksum = 0 (exit code) — ✓ all match
• alloc: checksum = 64 (exit code) — ✓ all match
• fnptr: checksum = 0 (exit code) — ✓ all match
• map: checksum = 192 (exit code) — ✓ all match
• map_kernel: checksum = 192 (exit code) — ✓ all match
• math: checksum = 0 (exit code) — ✓ all match

Workloads#

• fib — naive recursive Fibonacci summed over 0..31 (function-call / stack-frame cost).
• pi — Leibniz series, 2×10⁷ terms, float64 (FP throughput; cleanest cross-language compare).
• collatz — sum of Collatz stopping times for 1..699 999 (integer ALU + unpredictable branches).
• dispatch — 8×10⁶ virtual calls over a heterogeneous, heap-owned collection of mixed concrete types built at runtime, so the concrete type is not knowable at the call site and the call cannot be devirtualized — a true dynamic-dispatch measurement. Each language uses its idiomatic owning collection (kama DynamicArray<Owned<Shape>>, C++ vector<unique_ptr>, Rust Vec<Box<dyn>>, C array of heap Shape*, Go []interface, C#/Java Shape[]).
• alloc — 2000× (build a growable list, append 1..1000, sum, drop) ≈ 2M appends + 2000 lifetimes (allocator / GC pressure vs RAII; each language uses its idiomatic growable list — kama DynamicArray<int32>, C++ vector, Rust Vec, Go slice, C# List, Java ArrayList, Lua table, Python/JS array, C manual realloc).
• fnptr — 8×10⁶ indirect calls through a function pointer, routed through a function boundary (apply(op, x)) so the call stays genuinely indirect (the fnptr analog of dispatch's virtual calls). Each language uses its idiomatic callable — kama fnptr (a bare C function pointer, zero-cost), C/C++ function pointers, Rust fn pointers, Go func values, C# Func<> delegates, Java LongUnaryOperator method refs, Lua/Python/JS functions.
• map_kernel — the hash-map codegen row: every language runs the same hand-rolled open-addressing (linear-probe) int32 -> int64 map — one shared hash (a single 32-bit Fibonacci multiply), the same fixed 262 144-slot preallocation, no stdlib map anywhere. Insert 100 000 keys, then look every key up 10× in a scrambled (bijective LCG) order. Because the algorithm, hash, and capacity are pinned, this is the row that answers "is kama on par with C?" — the AOT cluster (kama/C/C++/Rust) should converge, exactly as it does on the compute kernels. (TS is absent here and in map/math: its tsconfig.json compiles only fib/pi/collatz/dispatch/alloc/fnptr.)
• map — the hash-map library-design row: the same workload, but each language uses its idiomatic map — kama Map<int32, int64>, C++ unordered_map, Rust HashMap, Go map, C# Dictionary, Java HashMap (boxed), Lua table, Python dict, JS Map. ⚠️ This measures map DESIGN, not codegen — hash strength, growth policy, and layout all differ, so the languages legitimately do not cluster. C is absent by design, not by omission: C has no stdlib hashmap. Its hand-rolled map is what map_kernel runs, in every language at once; entering that bespoke, preallocated structure here and ranking it against everyone else's general-purpose library maps would read as a codegen win when the actual finding is the trivial "a purpose-built preallocated map beats a general-purpose one". Every map that can be pre-sized is (see Methodology — pre-sizing), so what remains is hash and layout: kama 5.24 ms, C++ unordered_map 4.9 ms, Rust HashMap 8.27 ms. kama keeps its stronger default hash (splitmix64, two dependent 64-bit multiplies) here; the pluggable H: Hasher slot's FastHasher is map_kernel's single Fibonacci multiply, so a program that wants that tradeoff writes Map<int32, int64, FastHasher>. It is deliberately NOT used here: tuning one language's hash while the others stay idiomatic would tilt the row. That is what map_kernel is for.
• math — 2×10⁶ iterations of the std::math hot ops an engine leans on: Vec4 add/sub/scale, dot, Mat4*Vec4, Mat4*Mat4, and the Quat Hamilton product. Every input is a small integer-valued float32 so all intermediates are exactly representable (|v| < 2^24) — the checksum is therefore bit-identical across the float32 (kama/C/C++/Rust/Go) and float64 (JS/Lua/Python) backends. This is a codegen/SIMD-vectorization number: kama's math types carry a SIMD-ready layout, so this row tracks whether the field-by-field ops lower to packed SIMD as the backend evolves. (There is no SIMD campaign and no explicit vector surface — vectorization is the C backend's, earned by the layout plus release inlining; see SPEC.md Math.)

NATIVE — execution time (median, ms)#

NATIVE — peak resident memory (MB)#

NATIVE — package size#

What you ship: a self-contained binary needs no runtime; managed/interpreted rows are the assembly/source only and additionally require the noted runtime (.NET / JVM / interpreter). The size column is each language's fib artifact; the range spans every workload it built. C# and Java ship one multi-workload assembly, so their size is the same everywhere.

NATIVE — compile time#

Wall-clock to compile that language's bench artifacts (single build, not averaged). The compiled languages build one binary per workload (binaries built — 9 workloads; C skips map); C# and Java build one multi-workload binary that dispatches on args[0]. kama's figure is transpile-to-C plus clang. Interpreted languages (Lua, Python, JS) have no compile step and are omitted.

WASM track — execution time under node (median, ms)#

WASM track — peak resident memory (MB)#

WASM track — module size#

The size column is each language's fib artifact; the range spans every workload it built.

WASM track — compile time#

kama→wasm is transpile-to-C plus emcc -O3; TS is tsc. Hand-written JS has no compile step.

Caveats#

• dispatch measures true dynamic dispatch. An earlier variant called two stack locals of known final type, which let optimizers (notably rustc) devirtualize the call to plain arithmetic — comparing Rust's devirtualized code against everyone else's real indirect calls (a ~5× artifact). The current variant dispatches over a heap-owned heterogeneous collection the optimizer cannot resolve, so every AOT language performs a genuine vtable call: Rust converges to C (the artifact is gone) and kama ties the C/C++/Rust cluster. Only Go's interface dispatch trails (~2×).
• arm64 results — not comparable to x86 runs (arch recorded above).
• JIT warmup (C#, Java, node): mitigated by hyperfine warmups; tiny workloads still partly reflect startup. Java (HotSpot) has the heaviest fixed startup here, so startup-dominated workloads (e.g. fib) understate the warmed-up steady-state a long-running app like Minecraft gets from HotSpot's C2 tier; the longer compute loops (pi/collatz/dispatch/fnptr) still tier up within a run.
• Container overhead applies equally to all languages, so relative numbers are fair; absolute numbers carry slight overhead.
• C# AOT is built best-effort (bench/build/csharp-aot); the table shows the JIT runtime.
• Numbers are a snapshot to guide optimization, regenerated by bench/run all; do not hand-edit.

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