diff --git a/deep-js-stacks/README.md b/deep-js-stacks/README.md
new file mode 100644
index 0000000..869394a
--- /dev/null
+++ b/deep-js-stacks/README.md
@@ -0,0 +1,10 @@
+# deep-js-stacks
+
+This test case exists to show what happens to JS callstacks at around 256 frames tall.
+
+The known bug: the v8 sampling profiler only emits the _top-most_\* 256 callframes on the stack.
+
+\* Visually in the flamechart it's the bottom-most.
+
+
+
diff --git a/deep-js-stacks/app.js b/deep-js-stacks/app.js
new file mode 100644
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+++ b/deep-js-stacks/app.js
@@ -0,0 +1,46 @@
+// The problem manifests at a stack depth of 256, but startDemo and stall count as well.
+const lowBound = 248;
+const highBound = 256;
+// Additionally, worth pointing out that the named functions (call250, call252, etc) may not appear at exactly that index in the stack. For extra debugging fun. :)
+
+const output = document.getElementById('output');
+let currentMaxDepth = 0;
+
+function stall() {
+ const start = Date.now();
+ while (Date.now() - start < 0.5) {}
+}
+
+function startDemo() {
+ const start = performance.now();
+
+ for (let maxDepth = lowBound; maxDepth <= highBound; maxDepth++) {
+ currentMaxDepth = maxDepth;
+ call0();
+ }
+ for (let maxDepth = highBound; maxDepth >= lowBound; maxDepth--) {
+ currentMaxDepth = maxDepth;
+ call0();
+ }
+
+ const measure = performance.measure(
+ `stack-calling ${lowBound}-${highBound}`,
+ { start, end: performance.now() },
+ );
+
+ output.textContent += `Total execution time: ${measure.duration.toLocaleString()}ms\n`;
+}
+
+// Generate all the call functions
+for (let i = highBound; i >= 0; i--) {
+ window[`call${i}`] = new Function(`return function call${i}() {
+ if (${i} > currentMaxDepth) return;
+ if (${i} === currentMaxDepth) stall();
+ else call${i + 1}();
+
+ ${i % 4 === 0 ? `//# sourceURL=colorcall${i}.js \n` : ''}
+ }`)();
+}
+
+startDemo();
+document.querySelector('button').addEventListener('click', startDemo);
diff --git a/deep-js-stacks/index.html b/deep-js-stacks/index.html
new file mode 100644
index 0000000..7595c18
--- /dev/null
+++ b/deep-js-stacks/index.html
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+
+
+
+ Generate icicles ~256 entries high
+
+
+
+
+
+
+
diff --git a/index.html b/index.html
index 1d2263f..25a9d5e 100644
--- a/index.html
+++ b/index.html
@@ -10,6 +10,7 @@
basic-samples-stack
changing-resource-priority
console-timings
+deep-js-stacks
forced-layout-main-thread
gpu-tasks
idle-callback-time