diff --git a/runtime/native/dalvik_system_VMDebug.cc b/runtime/native/dalvik_system_VMDebug.cc
index 6a04c3a..4a84cfe 100644
--- a/runtime/native/dalvik_system_VMDebug.cc
+++ b/runtime/native/dalvik_system_VMDebug.cc
@@ -66,7 +66,8 @@
 }
 
 static void VMDebug_startMethodTracingFd(JNIEnv* env, jclass, jstring javaTraceFilename,
-                                         jobject javaFd, jint bufferSize, jint flags) {
+                                         jobject javaFd, jint bufferSize, jint flags,
+                                         jboolean samplingEnabled, jint intervalUs) {
   int originalFd = jniGetFDFromFileDescriptor(env, javaFd);
   if (originalFd < 0) {
     return;
@@ -85,16 +86,17 @@
   if (traceFilename.c_str() == NULL) {
     return;
   }
-  Trace::Start(traceFilename.c_str(), fd, bufferSize, flags, false, false, 0);
+  Trace::Start(traceFilename.c_str(), fd, bufferSize, flags, false, samplingEnabled, intervalUs);
 }
 
 static void VMDebug_startMethodTracingFilename(JNIEnv* env, jclass, jstring javaTraceFilename,
-                                               jint bufferSize, jint flags) {
+                                               jint bufferSize, jint flags,
+                                               jboolean samplingEnabled, jint intervalUs) {
   ScopedUtfChars traceFilename(env, javaTraceFilename);
   if (traceFilename.c_str() == NULL) {
     return;
   }
-  Trace::Start(traceFilename.c_str(), -1, bufferSize, flags, false, false, 0);
+  Trace::Start(traceFilename.c_str(), -1, bufferSize, flags, false, samplingEnabled, intervalUs);
 }
 
 static jint VMDebug_getMethodTracingMode(JNIEnv*, jclass) {
@@ -325,8 +327,8 @@
   NATIVE_METHOD(VMDebug, startEmulatorTracing, "()V"),
   NATIVE_METHOD(VMDebug, startInstructionCounting, "()V"),
   NATIVE_METHOD(VMDebug, startMethodTracingDdmsImpl, "(IIZI)V"),
-  NATIVE_METHOD(VMDebug, startMethodTracingFd, "(Ljava/lang/String;Ljava/io/FileDescriptor;II)V"),
-  NATIVE_METHOD(VMDebug, startMethodTracingFilename, "(Ljava/lang/String;II)V"),
+  NATIVE_METHOD(VMDebug, startMethodTracingFd, "(Ljava/lang/String;Ljava/io/FileDescriptor;IIZI)V"),
+  NATIVE_METHOD(VMDebug, startMethodTracingFilename, "(Ljava/lang/String;IIZI)V"),
   NATIVE_METHOD(VMDebug, stopAllocCounting, "()V"),
   NATIVE_METHOD(VMDebug, stopEmulatorTracing, "()V"),
   NATIVE_METHOD(VMDebug, stopInstructionCounting, "()V"),
diff --git a/runtime/trace.cc b/runtime/trace.cc
index da2c80a..2dac71e 100644
--- a/runtime/trace.cc
+++ b/runtime/trace.cc
@@ -299,6 +299,7 @@
 void* Trace::RunSamplingThread(void* arg) {
   Runtime* runtime = Runtime::Current();
   int interval_us = reinterpret_cast<int>(arg);
+  CHECK_GE(interval_us, 0);
   CHECK(runtime->AttachCurrentThread("Sampling Profiler", true, runtime->GetSystemThreadGroup(),
                                      !runtime->IsCompiler()));