From e3eec33b2475e3e4b1a0fd771145e349ef088826 Mon Sep 17 00:00:00 2001
From: Alexander Shabalin <alexander.shabalin@jetbrains.com>
Date: Wed, 9 Jun 2021 16:45:30 +0300
Subject: [PATCH] Add aggressively allocating stress test for GC

---
 .../backend.native/tests/build.gradle         |  5 ++
 .../runtime/memory/stress_gc_allocations.kt   | 83 +++++++++++++++++++
 2 files changed, 88 insertions(+)
 create mode 100644 kotlin-native/backend.native/tests/runtime/memory/stress_gc_allocations.kt

diff --git a/kotlin-native/backend.native/tests/build.gradle b/kotlin-native/backend.native/tests/build.gradle
index 873e6992a8a..8ba56a7a9ae 100644
--- a/kotlin-native/backend.native/tests/build.gradle
+++ b/kotlin-native/backend.native/tests/build.gradle
@@ -2953,6 +2953,11 @@ standaloneTest("leakMemoryWithTestRunner") {
     }
 }
 
+standaloneTest("stress_gc_allocations") {
+    source = "runtime/memory/stress_gc_allocations.kt"
+    flags = ['-tr', '-Xopt-in=kotlin.native.internal.InternalForKotlinNative']
+}
+
 standaloneTest("mpp1") {
     source = "codegen/mpp/mpp1.kt"
     flags = ['-tr', '-Xmulti-platform']
diff --git a/kotlin-native/backend.native/tests/runtime/memory/stress_gc_allocations.kt b/kotlin-native/backend.native/tests/runtime/memory/stress_gc_allocations.kt
new file mode 100644
index 00000000000..035b965a314
--- /dev/null
+++ b/kotlin-native/backend.native/tests/runtime/memory/stress_gc_allocations.kt
@@ -0,0 +1,83 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+import kotlin.test.*
+
+import kotlin.native.concurrent.*
+import kotlin.native.internal.MemoryUsageInfo
+
+object Blackhole {
+    private val hole = AtomicLong(0)
+
+    fun consume(value: Any) {
+        hole.addAndGet(value.hashCode())
+    }
+
+    fun discharge() {
+        println(hole.value)
+    }
+}
+
+// Keep a class to ensure we allocate in heap.
+// TODO: Protect it from escape analysis.
+class MemoryHog(val size: Int, val value: Byte, val stride: Int) {
+    val data = ByteArray(size)
+
+    init {
+        for (i in 0 until size step stride) {
+            data[i] = value
+        }
+        Blackhole.consume(data)
+    }
+}
+
+val peakRssBytes: Long
+    get() {
+        val value = MemoryUsageInfo.peakResidentSetSizeBytes
+        if (value == 0L) {
+            fail("Error trying to obtain peak RSS. Check if current platform is supported")
+        }
+        return value
+    }
+
+@Test
+fun test() {
+    // One item is ~10MiB.
+    val size = 10_000_000
+    // Total amount is ~1TiB.
+    val count = 100_000
+    val value: Byte = 42
+    // Try to make sure each page is written
+    val stride = 4096
+    // Limit memory usage at ~200MiB
+    val rssDiffLimit: Long = 200_000_000
+    // Trigger GC after ~100MiB are allocated
+    val retainLimit: Long = 100_000_000
+    val progressReportsCount = 100
+
+    if (Platform.memoryModel == MemoryModel.EXPERIMENTAL) {
+        kotlin.native.internal.GC.thresholdAllocations = retainLimit
+        // Effectively disable trigger on safepoints.
+        kotlin.native.internal.GC.threshold = Int.MAX_VALUE
+    }
+
+    // On Linux, the child process might immediately commit the same amount of memory as the parent.
+    // So, measure difference between peak RSS measurements.
+    val initialPeakRss = peakRssBytes
+
+    for (i in 0..count) {
+        if (i % (count / progressReportsCount) == 0) {
+            println("Allocating iteration ${i + 1} of $count")
+        }
+        MemoryHog(size, value, stride)
+        val diffPeakRss = peakRssBytes - initialPeakRss
+        if (diffPeakRss > rssDiffLimit) {
+            // If GC does not exist, this should eventually fail.
+            fail("Increased peak RSS by $diffPeakRss which is more than $rssDiffLimit")
+        }
+    }
+
+    // Make sure `Blackhole` does not get optimized out.
+    Blackhole.discharge()
+}