Trivial prototype of JFR context

Author: jbachorik

make/src/classes/build/tools/jfr/GenerateJfrFiles.java

@@ -204,6 +204,7 @@ static class TypeElement {
         boolean isEvent;
         boolean isRelation;
         boolean supportStruct = false;
+        boolean withContext = false;
         String commitState;
         public boolean primitive;
 
@@ -227,6 +228,7 @@ public void persist(DataOutputStream pos) throws IOException {
             pos.writeLong(id);
             pos.writeBoolean(isEvent);
             pos.writeBoolean(isRelation);
+            pos.writeBoolean(withContext);
         }
     }
 
@@ -524,6 +526,7 @@ public void startElement(String uri, String localName, String qName, Attributes
                 currentType.commitState = getString(attributes, "commitState");
                 currentType.isEvent = "Event".equals(qName);
                 currentType.isRelation = "Relation".equals(qName);
+                currentType.withContext = getBoolean(attributes, "withContext", false);
                 break;
             case "Field":
                 currentField = new FieldElement(metadata);
@@ -655,7 +658,8 @@ private static void printJfrEventControlHpp(Metadata metadata, File outputFile)
             out.write("  u1     stacktrace;");
             out.write("  u1     enabled;");
             out.write("  u1     large;");
-            out.write("  u1     pad[5]; // Because GCC on linux ia32 at least tries to pack this.");
+            out.write("  u1     context;");
+            out.write("  u1     pad[4]; // Because GCC on linux ia32 at least tries to pack this.");
             out.write("};");
             out.write("");
             out.write("union JfrNativeSettings {");
@@ -860,6 +864,7 @@ private static void printEvent(Printer out, TypeElement event, boolean empty) {
             out.write("  static const bool isInstant = " + !event.startTime + ";");
             out.write("  static const bool hasCutoff = " + event.cutoff + ";");
             out.write("  static const bool hasThrottle = " + event.throttle + ";");
+            out.write("  static const bool hasContext = " + event.withContext + ";");
             out.write("  static const bool isRequestable = " + !event.period.isEmpty() + ";");
             out.write("  static const JfrEventId eventId = Jfr" + event.name + "Event;");
             out.write("");

src/hotspot/share/jfr/jni/jfrJniMethod.cpp

@@ -43,6 +43,7 @@
 #include "jfr/instrumentation/jfrEventClassTransformer.hpp"
 #include "jfr/instrumentation/jfrJvmtiAgent.hpp"
 #include "jfr/leakprofiler/leakProfiler.hpp"
+#include "jfr/support/jfrContext.hpp"
 #include "jfr/support/jfrJdkJfrEvent.hpp"
 #include "jfr/support/jfrKlassUnloading.hpp"
 #include "jfr/utilities/jfrJavaLog.hpp"
@@ -397,3 +398,17 @@ JVM_END
 JVM_ENTRY_NO_ENV(void, jfr_emit_data_loss(JNIEnv* env, jclass jvm, jlong bytes))
   EventDataLoss::commit(bytes, min_jlong);
 JVM_END
+
+NO_TRANSITION(void, jfr_set_used_context_size(JNIEnv* env, jclass jvm, jint size))
+  JfrContext::set_used_context_size(size);
+NO_TRANSITION_END
+
+NO_TRANSITION(jboolean, jfr_is_context_enabled(JNIEnv* env, jclass jvmf))
+  return JfrOptionSet::is_context_enabled();
+NO_TRANSITION_END
+
+NO_TRANSITION(jobject, jfr_get_thread_context_buffer(JNIEnv* env, jclass jvm))
+  uint64_t* data;
+  uint8_t size = JfrContext::get_context(&data);
+  return env->NewDirectByteBuffer((void*)data, (jlong) size * 8);
+NO_TRANSITION_END

src/hotspot/share/jfr/jni/jfrJniMethod.hpp

@@ -159,6 +159,10 @@ jlong JNICALL jfr_host_total_memory(JNIEnv* env, jclass jvm);
 
 void JNICALL jfr_emit_data_loss(JNIEnv* env, jclass jvm, jlong bytes);
 
+void JNICALL jfr_set_used_context_size(JNIEnv* env, jclass jvm, jint size);
+jboolean JNICALL jfr_is_context_enabled(JNIEnv* env, jclass jvm);
+jobject JNICALL jfr_get_thread_context_buffer(JNIEnv* env, jclass jvm);
+
 #ifdef __cplusplus
 }
 #endif

src/hotspot/share/jfr/jni/jfrJniMethodRegistration.cpp

@@ -97,7 +97,10 @@ JfrJniMethodRegistration::JfrJniMethodRegistration(JNIEnv* env) {
       (char*)"isInstrumented", (char*)"(Ljava/lang/Class;)Z", (void*) jfr_is_class_instrumented,
       (char*)"isContainerized", (char*)"()Z", (void*) jfr_is_containerized,
       (char*)"hostTotalMemory", (char*)"()J", (void*) jfr_host_total_memory,
-      (char*)"emitDataLoss", (char*)"(J)V", (void*)jfr_emit_data_loss
+      (char*)"emitDataLoss", (char*)"(J)V", (void*)jfr_emit_data_loss,
+      (char*)"setUsedContextSize", (char*)"(I)V", (void*)jfr_set_used_context_size,
+      (char*)"isContextEnabled", (char*)"()Z", (void*)jfr_is_context_enabled,
+      (char*)"getThreadContextBuffer0", (char*)"()Ljava/lang/Object;", (void*)jfr_get_thread_context_buffer
     };
 
     const size_t method_array_length = sizeof(method) / sizeof(JNINativeMethod);

src/hotspot/share/jfr/metadata/metadata.xml

@@ -89,28 +89,28 @@
     <Field type="Thread" name="thread" label="Java Thread" />
   </Event>
 
-  <Event name="ThreadPark" category="Java Application" label="Java Thread Park" thread="true" stackTrace="true">
+  <Event name="ThreadPark" category="Java Application" label="Java Thread Park" thread="true" stackTrace="true" withContext="true">
     <Field type="Class" name="parkedClass" label="Class Parked On" />
     <Field type="long" contentType="nanos" name="timeout" label="Park Timeout" />
     <Field type="long" contentType="epochmillis" name="until" label="Park Until" />
     <Field type="ulong" contentType="address" name="address" label="Address of Object Parked" relation="JavaMonitorAddress" />
   </Event>
 
-  <Event name="JavaMonitorEnter" category="Java Application" label="Java Monitor Blocked" thread="true" stackTrace="true">
+  <Event name="JavaMonitorEnter" category="Java Application" label="Java Monitor Blocked" thread="true" stackTrace="true" withContext="true">
     <Field type="Class" name="monitorClass" label="Monitor Class" />
     <Field type="Thread" name="previousOwner" label="Previous Monitor Owner" />
     <Field type="ulong" contentType="address" name="address" label="Monitor Address" relation="JavaMonitorAddress" />
   </Event>
 
-  <Event name="JavaMonitorWait" category="Java Application" label="Java Monitor Wait" description="Waiting on a Java monitor" thread="true" stackTrace="true">
+  <Event name="JavaMonitorWait" category="Java Application" label="Java Monitor Wait" description="Waiting on a Java monitor" thread="true" stackTrace="true" withContext="true">
     <Field type="Class" name="monitorClass" label="Monitor Class" description="Class of object waited on" />
     <Field type="Thread" name="notifier" label="Notifier Thread" description="Notifying Thread" />
     <Field type="long" contentType="millis" name="timeout" label="Timeout" description="Maximum wait time" />
     <Field type="boolean" name="timedOut" label="Timed Out" description="Wait has been timed out" />
     <Field type="ulong" contentType="address" name="address" label="Monitor Address" description="Address of object waited on" relation="JavaMonitorAddress" />
   </Event>
 
-  <Event name="JavaMonitorInflate" category="Java Application" label="Java Monitor Inflated" thread="true" stackTrace="true">
+  <Event name="JavaMonitorInflate" category="Java Application" label="Java Monitor Inflated" thread="true" stackTrace="true" withContext="true">
     <Field type="Class" name="monitorClass" label="Monitor Class" />
     <Field type="ulong" contentType="address" name="address" label="Monitor Address" relation="JavaMonitorAddress" />
     <Field type="InflateCause" name="cause" label="Monitor Inflation Cause" description="Cause of inflation" />
@@ -727,7 +727,7 @@
     <Field type="ulong" contentType="bytes" name="allocationSize" label="Allocation Size" />
   </Event>
 
-  <Event name="ObjectAllocationSample" category="Java Application" label="Object Allocation Sample" thread="true" stackTrace="true" startTime="false" throttle="true">
+  <Event name="ObjectAllocationSample" category="Java Application" label="Object Allocation Sample" thread="true" stackTrace="true" startTime="false" throttle="true" withContext="true">
     <Field type="Class" name="objectClass" label="Object Class" description="Class of allocated object" />
     <Field type="long" contentType="bytes" name="weight" label="Sample Weight"
       description="The relative weight of the sample. Aggregating the weights for a large number of samples, for a particular class, thread or stack trace, gives a statistically accurate representation of the allocation pressure" />
@@ -915,7 +915,7 @@
   </Event>
 
   <Event name="ExecutionSample" category="Java Virtual Machine, Profiling" label="Method Profiling Sample" description="Snapshot of a threads state"
-    period="everyChunk">
+    period="everyChunk" withContext="true">
     <Field type="Thread" name="sampledThread" label="Thread" />
     <Field type="StackTrace" name="stackTrace" label="Stack Trace" />
     <Field type="ThreadState" name="state" label="Thread State" />

src/hotspot/share/jfr/metadata/metadata.xsd

@@ -72,6 +72,7 @@
               <xs:attribute name="period" type="periodType" use="optional" />
               <xs:attribute name="cutoff" type="xs:boolean" use="optional" />
               <xs:attribute name="throttle" type="xs:boolean" use="optional" />
+              <xs:attribute name="withContext" type="xs:boolean" use="optional" />
             </xs:complexType>
           </xs:element>
           <xs:element maxOccurs="unbounded" name="Type">

src/hotspot/share/jfr/recorder/service/jfrEvent.hpp

@@ -28,6 +28,7 @@
 #include "jfr/recorder/jfrEventSetting.inline.hpp"
 #include "jfr/recorder/service/jfrEventThrottler.hpp"
 #include "jfr/recorder/stacktrace/jfrStackTraceRepository.hpp"
+#include "jfr/support/jfrContext.hpp"
 #include "jfr/utilities/jfrTime.hpp"
 #include "jfr/utilities/jfrTypes.hpp"
 #include "jfr/writers/jfrNativeEventWriter.hpp"
@@ -243,6 +244,13 @@ class JfrEvent {
     if (T::hasStackTrace) {
       writer.write(sid);
     }
+    if (T::hasContext) {
+      uint64_t* data;
+      uint8_t ctx_len = JfrContext::get_context(&data);
+      for (uint8_t i = 0; i < ctx_len; i++) {
+        writer.write(data[i]);
+      }
+    }
     // Payload.
     static_cast<T*>(this)->writeData(writer);
     return writer.end_event_write(large_size) > 0;

src/hotspot/share/jfr/recorder/service/jfrOptionSet.hpp

@@ -47,6 +47,7 @@ class JfrOptionSet : public AllStatic {
   static u4 _stack_depth;
   static jboolean _retransform;
   static jboolean _sample_protection;
+  static jboolean _context;
 
   static bool initialize(JavaThread* thread);
   static bool configure(TRAPS);
@@ -74,6 +75,12 @@ class JfrOptionSet : public AllStatic {
   static bool allow_event_retransforms();
   static bool sample_protection();
   DEBUG_ONLY(static void set_sample_protection(jboolean protection);)
+  static void enable_context() {
+    _context = true;
+  }
+  static bool is_context_enabled() {
+    return true; // _context;
+  }
 
   static bool parse_flight_recorder_option(const JavaVMOption** option, char* delimiter);
   static bool parse_start_flight_recording_option(const JavaVMOption** option, char* delimiter);

src/hotspot/share/jfr/support/jfrContext.cpp

@@ -0,0 +1,67 @@
+#include "precompiled.hpp"
+#include "jfrContext.hpp"
+#include "jfr/support/jfrThreadLocal.hpp"
+#include "runtime/thread.hpp"
+
+#ifndef MIN
+#define MIN(a,b) ((a) < (b) ? (a) : (b))
+#endif
+
+uint8_t JfrContext::_size = 0;
+
+JfrThreadLocal* getThreadLocal() {
+    Thread* thrd = Thread::current_or_null_safe();
+    return thrd != nullptr ? thrd->jfr_thread_local() : nullptr;
+}
+
+void JfrContext::set_used_context_size(uint8_t size) {
+    assert(size <= 8, "max context size is 8");
+    _size = size;
+}
+
+uint64_t JfrContext::get_and_set_context(uint8_t idx, uint64_t value) {
+    JfrThreadLocal* jfrTLocal = getThreadLocal();
+    if (jfrTLocal != nullptr) {
+        uint64_t old_value = 0;
+        jfrTLocal->get_context(&old_value, 1, idx);
+        jfrTLocal->set_context(&value, 1, idx);
+        return old_value;
+    }
+    return 0;
+}
+
+uint8_t JfrContext::get_all_context(uint64_t* data, uint8_t length) {
+    JfrThreadLocal* jfrTLocal = getThreadLocal();
+    if (jfrTLocal != nullptr) {
+        return jfrTLocal->get_context(data, MIN(_size, length), 0);
+    }
+
+    return 0;
+}
+
+uint8_t JfrContext::get_context(uint64_t** data) {
+    void* buffer = get_thread_context_buffer();
+    if (buffer) {
+        *data = (uint64_t*) buffer;
+        return _size;
+    }
+    return 0;
+}
+
+uint8_t JfrContext::set_all_context(uint64_t* data, uint8_t length) {
+    JfrThreadLocal* jfrTLocal = getThreadLocal();
+    if (jfrTLocal != nullptr) {
+        jfrTLocal->set_context(data, MIN(_size, length), 0);
+        return length;
+    }
+
+    return 0;
+}
+
+void* JfrContext::get_thread_context_buffer() {
+    JfrThreadLocal* jfrTLocal = getThreadLocal();
+    if (jfrTLocal != nullptr) {
+        return (void*)jfrTLocal->get_context_buffer();
+    }
+    return nullptr;
+}

src/hotspot/share/jfr/support/jfrContext.hpp

@@ -0,0 +1,20 @@
+#ifndef SHARE_JFR_SUPPORT_CONTEXT_HPP
+#define SHARE_JFR_SUPPORT_CONTEXT_HPP
+
+#include "memory/allStatic.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+class JfrContext : AllStatic {
+ private:
+  static uint8_t _size;
+ public:
+  static void set_used_context_size(uint8_t size);
+  static inline uint8_t get_used_context_size() { return _size; }
+  static uint64_t get_and_set_context(uint8_t idx, uint64_t value);
+  static uint8_t get_all_context(uint64_t* data, uint8_t length);
+  static uint8_t set_all_context(uint64_t* data, uint8_t length);
+  static uint8_t get_context(uint64_t** data);
+  static void* get_thread_context_buffer();
+};
+
+#endif // SHARE_JFR_SUPPORT_CONTEXT_HPP