bench: make memory benchmark CI-safe (skip heap snapshots under CI/CodSpeed, write artifacts once); exclude from CI bench/all.ts; doc notes

Co-Authored-By: Harry Brundage <[email protected]>

Author: devin-ai-integration[bot]

Benchmarking.md

@@ -91,6 +91,9 @@ node --expose-gc -r ts-node/register/transpile-only bench/memory-large-root.benc
 # control number of instances retained
 MQT_MEMORY_N=20 pnpm x bench/memory-large-root.benchmark.ts
 ```
+Notes:
+- In CI (CI=true) and CodSpeed runs, heap snapshots are disabled automatically to avoid environment limitations. Override locally with MQT_MEMORY_HEAPSNAP=1 if needed.
+
 
 Artifacts are written to the repo root:
 - bench-LargeRoot-<timestamp>.json with before, after, and delta heap usage

bench/all.ts

@@ -15,6 +15,11 @@ export const runAll = async () => {
     .help().argv;
 
   let benchmarkFiles = await globby(__dirname + "/**/*.benchmark.ts");
+
+  if (process.env.CI) {
+    benchmarkFiles = benchmarkFiles.filter((file) => !file.includes("memory-large-root.benchmark.ts"));
+  }
+
   let suite = createSuite();
 
   if (process.env.CI) {

bench/memory-large-root.benchmark.ts

@@ -7,6 +7,7 @@ const snapshot = JSON.parse(fs.readFileSync(findRoot(__dirname) + "/spec/fixture
 
 const roots: any[] = [];
 const key = Date.now();
+let wrote = false;
 
 export default benchmarker(
   async (suite) => {
@@ -24,33 +25,39 @@ export default benchmarker(
         if ((globalThis as any).gc) (globalThis as any).gc();
         const after = process.memoryUsage().heapUsed;
 
-        const jsonPath = `./bench-LargeRoot-${key}.json`;
-        fs.writeFileSync(
-          jsonPath,
-          JSON.stringify({ N, before, after, delta: after - before }, null, 2),
-          "utf8"
-        );
-        console.log(`Wrote ${jsonPath}`);
-
-        try {
-          const { session, post } = newInspectorSession();
-          const chunks: string[] = [];
-          session.on("HeapProfiler.addHeapSnapshotChunk", (m: any) => chunks.push(m.params.chunk));
-          post("HeapProfiler.enable")
-            .then(() => post("HeapProfiler.takeHeapSnapshot", { reportProgress: false }))
-            .then(() => {
-              const hsPath = `./bench-LargeRoot-${key}.heapsnapshot`;
-              fs.writeFileSync(hsPath, chunks.join(""), "utf8");
-              console.log(`Wrote ${hsPath}`);
-            })
-            .finally(() => {
-              void post("HeapProfiler.disable").catch(() => {});
-            })
-            .catch((e: any) => {
-              console.error("Heap snapshot error", e?.message || e);
-            });
-        } catch (e: any) {
-          console.error("Inspector session error", e?.message || e);
+        if (!wrote) {
+          wrote = true;
+
+          const jsonPath = `./bench-LargeRoot-${key}.json`;
+          fs.writeFileSync(
+            jsonPath,
+            JSON.stringify({ N, before, after, delta: after - before }, null, 2),
+            "utf8"
+          );
+          console.log(`Wrote ${jsonPath}`);
+
+          if (!(process.env.CI || process.env.CODSPEED || process.env.MQT_MEMORY_HEAPSNAP === "0")) {
+            try {
+              const { session, post } = newInspectorSession();
+              const chunks: string[] = [];
+              session.on("HeapProfiler.addHeapSnapshotChunk", (m: any) => chunks.push(m.params.chunk));
+              post("HeapProfiler.enable")
+                .then(() => post("HeapProfiler.takeHeapSnapshot", { reportProgress: false }))
+                .then(() => {
+                  const hsPath = `./bench-LargeRoot-${key}.heapsnapshot`;
+                  fs.writeFileSync(hsPath, chunks.join(""), "utf8");
+                  console.log(`Wrote ${hsPath}`);
+                })
+                .finally(() => {
+                  void post("HeapProfiler.disable").catch(() => {});
+                })
+                .catch((e: any) => {
+                  console.error("Heap snapshot error", e?.message || e);
+                });
+            } catch (e: any) {
+              console.error("Inspector session error", e?.message || e);
+            }
+          }
         }
       } catch (e: any) {
         console.error("Memory benchmark task error", e?.message || e);