From 4880231ff710058cbca7c5ea63d4a8c5f6591c99 Mon Sep 17 00:00:00 2001
From: Peter Steinberger <peter@steipete.me>
Date: Fri, 17 Jul 2026 11:07:59 +0100
Subject: [PATCH] perf(ci): correct pack hints from measured stripe walls
 (#109899)

Group walls measured from compact run 29564411446 (post-#109769):
core-unit-fast-isolated runs 78.6s on 4 vCPU because fork-per-file
isolation parallelizes poorly there; pin it to the 8 vCPU class where
the same segment runs ~50s. Unit-fast stripes measure ~25-37s (hinted
100/60) and tooling stripes 71-87s; refresh both so the packer stops
overfilling small bins (the 299s compact tail this run produced).
Cheap stripes may now co-locate in one bin, so the compact test only
requires their presence.
---
 scripts/lib/ci-node-test-plan.mjs      | 21 +++++++++++++--------
 test/scripts/ci-node-test-plan.test.ts |  3 +--
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/scripts/lib/ci-node-test-plan.mjs b/scripts/lib/ci-node-test-plan.mjs
index 836ee75ed8b9..7314333f2d7d 100644
--- a/scripts/lib/ci-node-test-plan.mjs
+++ b/scripts/lib/ci-node-test-plan.mjs
@@ -125,14 +125,18 @@ const COMPACT_GROUP_SECONDS_HINTS = new Map([
   // PTY timing suites still need a lightly packed lane; the exclusive-bin cap
   // leaves only trivial co-groups next to this measured runtime.
   ["core-runtime-tui-pty", 103],
-  ["core-tooling-1", 85],
-  ["core-tooling-2", 112],
-  ["core-tooling-3", 106],
-  ["core-tooling-4", 105],
-  ["core-tooling-isolated", 58],
-  ["core-unit-fast-1", 60],
-  ["core-unit-fast-2", 60],
-  ["core-unit-fast-isolated", 25],
+  // Stripe walls measured from compact run 29564411446 group timestamps.
+  ["core-tooling-1", 87],
+  ["core-tooling-2", 80],
+  ["core-tooling-3", 82],
+  ["core-tooling-4", 71],
+  ["core-tooling-isolated", 45],
+  ["core-unit-fast-1", 40],
+  ["core-unit-fast-2", 40],
+  // Fork-per-file isolation parallelizes poorly on 4 vCPU (78.6s measured in
+  // compact run 29564411446); keep it on the 8 vCPU class where the same
+  // segment runs ~50s.
+  ["core-unit-fast-isolated", 50],
   ["core-unit-src-security", 108],
   ["core-unit-support", 15],
 ]);
@@ -256,6 +260,7 @@ const KEEP_LARGE_NODE_TEST_RUNNER = new Set([
   "core-runtime-media-ui",
   "core-unit-fast-1",
   "core-unit-fast-2",
+  "core-unit-fast-isolated",
   "core-unit-src-security",
 ]);
 const RELEASE_ONLY_PLUGIN_SHARDS = new Set(["agentic-plugins"]);
diff --git a/test/scripts/ci-node-test-plan.test.ts b/test/scripts/ci-node-test-plan.test.ts
index 4b55d2e9940c..4c1358936952 100644
--- a/test/scripts/ci-node-test-plan.test.ts
+++ b/test/scripts/ci-node-test-plan.test.ts
@@ -242,10 +242,9 @@ describe("scripts/lib/ci-node-test-plan.mjs", () => {
     const jobOf = (name: string) =>
       compact.findIndex((shard) => shard.groups.some((group) => group.shard_name === name));
     expect(jobOf("agentic-agents-core-runner-embedded")).toBeGreaterThanOrEqual(0);
+    // Cheap stripes may legally co-locate in one bin; only existence matters.
     expect(jobOf("core-unit-fast-1")).toBeGreaterThanOrEqual(0);
     expect(jobOf("core-unit-fast-2")).toBeGreaterThanOrEqual(0);
-    expect(jobOf("core-unit-fast-1")).not.toBe(jobOf("core-unit-fast-2"));
-    expect(jobOf("agentic-agents-core-runner-embedded")).not.toBe(jobOf("core-unit-fast-1"));
     // Spawn/signal-timing suites never mix with regular groups, and every
     // compact bin runs serially: overlapping Vitest runs flake timing-
     // sensitive tests on both runner classes.