Add a separate aggressive GC mode

kotlin-native/runtime/src/gc/stms/cpp/SameThreadMarkAndSweep.cpp

@@ -109,6 +109,14 @@ void gc::SameThreadMarkAndSweep::ThreadData::SafePointRegular(size_t weight) noe
     safePointsCounter_ += weight;
 }
 
+gc::SameThreadMarkAndSweep::SameThreadMarkAndSweep() noexcept {
+    if (Kotlin_getGcAggressive()) {
+        // TODO: Make it even more aggressive and run on a subset of backend.native tests.
+        threshold_ = 1000;
+        allocationThresholdBytes_ = 10000;
+    }
+}
+
 mm::ObjectFactory<gc::SameThreadMarkAndSweep>::FinalizerQueue gc::SameThreadMarkAndSweep::PerformFullGC() noexcept {
     bool didSuspend = mm::SuspendThreads();
     if (!didSuspend) {

kotlin-native/runtime/src/gc/stms/cpp/SameThreadMarkAndSweep.hpp

@@ -63,7 +63,7 @@ public:
         size_t safePointsCounter_ = 0;
     };
 
-    SameThreadMarkAndSweep() noexcept {}
+    SameThreadMarkAndSweep() noexcept;
     ~SameThreadMarkAndSweep() = default;
 
     void SetThreshold(size_t value) noexcept { threshold_ = value; }
@@ -78,8 +78,8 @@ public:
 private:
     mm::ObjectFactory<SameThreadMarkAndSweep>::FinalizerQueue PerformFullGC() noexcept;
 
-    size_t threshold_ = 1000;
-    size_t allocationThresholdBytes_ = 10000;
+    size_t threshold_ = 100000;  // Roughly 1 safepoint per 10ms (on a subset of examples on one particular machine).
+    size_t allocationThresholdBytes_ = 10 * 1024 * 1024;  // 10MiB by default.
     bool autoTune_ = false;
 };
 

kotlin-native/runtime/src/main/cpp/Runtime.cpp

@@ -31,13 +31,18 @@ struct InitNode {
   InitNode* next;
 };
 
-// This global is overriden by the compiler.
+// These globals are overriden by the compiler.
 RUNTIME_WEAK DestroyRuntimeMode Kotlin_destroyRuntimeMode = DESTROY_RUNTIME_ON_SHUTDOWN;
+RUNTIME_WEAK KInt Kotlin_gcAggressive = 0;
 
 DestroyRuntimeMode Kotlin_getDestroyRuntimeMode() {
     return Kotlin_destroyRuntimeMode;
 }
 
+bool Kotlin_getGcAggressive() {
+    return Kotlin_gcAggressive != 0;
+}
+
 namespace {
 
 InitNode* initHeadNode = nullptr;

kotlin-native/runtime/src/main/cpp/Runtime.h

@@ -32,6 +32,7 @@ enum DestroyRuntimeMode {
 };
 
 DestroyRuntimeMode Kotlin_getDestroyRuntimeMode();
+bool Kotlin_getGcAggressive();
 
 // For experimental MM, if runtime gets initialized, it will be in the native state after this.
 RUNTIME_NOTHROW void Kotlin_initRuntimeIfNeeded();