[Autoloop: perf-comparison] Iteration 413: add readHdf/toHdf benchmark pair

Run: https://github.com/githubnext/tsb/actions/runs/29792948080

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: github-actions[bot]

benchmarks/pandas/bench_readHdf.py

@@ -0,0 +1,36 @@
+"""Benchmark: read_hdf / to_hdf — HDF5 round-trip on a 10k-row DataFrame"""
+import json, time, io
+import numpy as np
+import pandas as pd
+
+ROWS = 10_000
+WARMUP = 3
+ITERATIONS = 20
+
+rng = np.arange(ROWS)
+df = pd.DataFrame({
+    "id": rng,
+    "value": rng * 1.23456,
+    "flag": rng % 2,
+})
+
+tmp_path = "/tmp/gh-aw/agent/bench_readHdf.h5"
+
+def roundtrip():
+    df.to_hdf(tmp_path, key="df", mode="w")
+    pd.read_hdf(tmp_path, key="df")
+
+for _ in range(WARMUP):
+    roundtrip()
+
+start = time.perf_counter()
+for _ in range(ITERATIONS):
+    roundtrip()
+total = (time.perf_counter() - start) * 1000
+
+print(json.dumps({
+    "function": "readHdf",
+    "mean_ms": total / ITERATIONS,
+    "iterations": ITERATIONS,
+    "total_ms": total,
+}))

benchmarks/tsb/bench_readHdf.ts

@@ -0,0 +1,44 @@
+/**
+ * Benchmark: readHdf / toHdf — HDF5 round-trip on a 10k-row DataFrame
+ */
+import { DataFrame } from "../../src/index.js";
+import { readHdf, toHdf } from "../../src/index.js";
+
+const ROWS = 10_000;
+const WARMUP = 3;
+const ITERATIONS = 20;
+
+// Build a DataFrame with mixed numeric and string columns
+const ids = new Array<number>(ROWS).fill(0).map((_, i) => i);
+const values = new Array<number>(ROWS).fill(0).map((_, i) => i * 1.23456);
+const flags = new Array<number>(ROWS).fill(0).map((_, i) => i % 2);
+
+const df = DataFrame.fromColumns({
+  id: ids,
+  value: values,
+  flag: flags,
+});
+
+// Pre-serialise once so both readHdf and toHdf are benchmarked together
+const buf = toHdf(df);
+
+for (let i = 0; i < WARMUP; i++) {
+  const out = toHdf(df);
+  readHdf(out);
+}
+
+const start = performance.now();
+for (let i = 0; i < ITERATIONS; i++) {
+  const out = toHdf(df);
+  readHdf(out);
+}
+const total = performance.now() - start;
+
+console.log(
+  JSON.stringify({
+    function: "readHdf",
+    mean_ms: total / ITERATIONS,
+    iterations: ITERATIONS,
+    total_ms: total,
+  }),
+);