1 files changed, 36 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/debug/Memory-allocationSamplingProbability-02.js b/js/src/jit-test/tests/debug/Memory-allocationSamplingProbability-02.js
new file mode 100644
index 0000000000..bbd2582a68
--- /dev/null
+++ b/js/src/jit-test/tests/debug/Memory-allocationSamplingProbability-02.js
@@ -0,0 +1,36 @@
+// Test that we only sample about allocationSamplingProbability * 100 percent of
+// allocations.
+
+const root = newGlobal({newCompartment: true});
+
+const dbg = new Debugger();
+const wrappedRoot = dbg.addDebuggee(root);
+
+root.eval(`
+  objs = [];
+  objs.push(new Object);
+`);
+
+root.eval("" + function makeSomeAllocations() {
+  for (var i = 0; i < 100; i++) {
+    objs.push(new Object);
+  }
+});
+
+function measure(P, expected) {
+  root.setSavedStacksRNGState(Number.MAX_SAFE_INTEGER - 1);
+  dbg.memory.allocationSamplingProbability = P;
+  root.makeSomeAllocations();
+  assertEq(dbg.memory.drainAllocationsLog().length, expected);
+}
+
+dbg.memory.trackingAllocationSites = true;
+
+// These are the sample counts that were correct when this test was last
+// updated; changes to SpiderMonkey may occasionally cause changes
+// here. Anything that is within a plausible range for the given sampling
+// probability is fine.
+measure(0.0, 0);
+measure(1.0, 100);
+measure(0.1, 11);
+measure(0.5, 49);