From c0f5c9bd803da2431f7ef82d0b9dba8c45d0ce75 Mon Sep 17 00:00:00 2001
From: Edward Thomson <ethomson@edwardthomson.com>
Date: Mon, 26 Jan 2026 21:51:54 +0000
Subject: [PATCH] ci: generate markdown results from benchmarks

---
 ci/compare-benchmarks.js | 99 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100755 ci/compare-benchmarks.js

diff --git a/ci/compare-benchmarks.js b/ci/compare-benchmarks.js
new file mode 100755
index 000000000..7646ed975
--- /dev/null
+++ b/ci/compare-benchmarks.js
@@ -0,0 +1,99 @@
+#!/usr/bin/env node
+
+const fs = require('fs');
+const process = require('node:process');
+
+const path = process.argv[2] || '.';
+const output = process.argv[3];
+
+const dirs = fs.readdirSync(path);
+
+tests = [ ];
+results = { };
+
+for (const dir of dirs) {
+    const name = dir.replace(/^results-/, '');
+
+    const control = JSON.parse(fs.readFileSync(`${path}/${dir}/control.json`));
+    const candidate = JSON.parse(fs.readFileSync(`${path}/${dir}/candidate.json`));
+
+    results[name] = { };
+
+    const controlTests = control.tests.map((x) => x.name);
+    const candidateTests = candidate.tests.map((x) => x.name);
+    tests = [...new Set(tests.concat(controlTests).concat(candidateTests))];
+
+    for (const test of tests) {
+        const controlResults = control.tests.filter((x) => x.name === test)[0];
+        const candidateResults = candidate.tests.filter((x) => x.name === test)[0];
+
+        let result;
+
+        if (controlResults.results.status === 'ok' &&
+            candidateResults.results.status === 'ok') {
+            const delta = (candidateResults.results.mean - controlResults.results.mean) / candidateResults.results.mean;
+            const deltaPercent = Math.round(Math.abs(delta) * 1000) / 10;
+            const direction = (delta > 0) ? 'slower' : 'faster';
+            let highlight = '';
+
+            if (delta > 0.1) {
+                highlight = '**';
+            }
+
+            results[name][test] = `${highlight}${deltaPercent}% ${direction}${highlight}`;
+        }
+        else if (controlResults.results.status === 'ok') {
+            results[name][test] = `${candidateResults.results.stauts} in candidate`;
+        }
+        else if (candidateResults.results.status === 'ok') {
+            results[name][test] = `${controlResults.results.stauts} in control`;
+        }
+        else {
+            results[name][test] = controlResults.results.status;
+        }
+    }
+}
+
+let markdown = '| Platform \\ Test |';
+
+for (const test in Object.values(results)[0]) {
+    markdown += ` ${test} |`;
+}
+markdown += '\n';
+
+markdown += `| --- |`;
+for (const test in Object.values(results)[0]) {
+    markdown += ` --- |`;
+}
+markdown += '\n';
+
+for (const name in results) {
+    markdown += `| ${name.replaceAll(/-/g, '&#x2011;')} |`;
+
+    for (const test in results[name]) {
+        markdown += ` ${results[name][test]} |`;
+    }
+
+    markdown += `\n`;
+}
+
+if (output) {
+    fs.writeFileSync(output, markdown);
+}
+else {
+    console.log(markdown);
+}
+
+function p(arr, q) {
+    const array = [...arr].sort();
+    const pos = (array.length - 1) * q;
+    const base = Math.floor(pos);
+    const rest = pos - base;
+
+    if (array[base + 1] !== undefined) {
+        return array[base] + rest * (array[base + 1] - array[base]);
+    }
+    else {
+        return array[base];
+    }
+}