WIP

Author: jbachorik

src/hotspot/share/gc/shared/allocTracer.cpp

@@ -32,7 +32,6 @@
 #endif
 
 void AllocTracer::send_allocation_outside_tlab(Klass* klass, HeapWord* obj, size_t alloc_size, JavaThread* thread) {
-  JFR_ONLY(JfrAllocationTracer tracer(klass, obj, alloc_size, true, thread);)
   EventObjectAllocationOutsideTLAB event;
   if (event.should_commit()) {
     event.set_objectClass(klass);
@@ -42,7 +41,6 @@ void AllocTracer::send_allocation_outside_tlab(Klass* klass, HeapWord* obj, size
 }
 
 void AllocTracer::send_allocation_in_new_tlab(Klass* klass, HeapWord* obj, size_t tlab_size, size_t alloc_size, JavaThread* thread) {
-  JFR_ONLY(JfrAllocationTracer tracer(klass, obj, alloc_size, false, thread);)
   EventObjectAllocationInNewTLAB event;
   if (event.should_commit()) {
     event.set_objectClass(klass);
@@ -52,6 +50,10 @@ void AllocTracer::send_allocation_in_new_tlab(Klass* klass, HeapWord* obj, size_
   }
 }
 
+void AllocTracer::send_allocation_sample(Klass* klass, HeapWord* obj, size_t alloc_size, size_t weight, bool large_allocation, JavaThread* thread) {
+  JFR_ONLY(JfrAllocationTracer tracer(klass, obj, alloc_size, large_allocation, thread);)
+}
+
 void AllocTracer::send_allocation_requiring_gc_event(size_t size, uint gcId) {
   EventAllocationRequiringGC event;
   if (event.should_commit()) {

src/hotspot/share/gc/shared/allocTracer.hpp

@@ -32,6 +32,7 @@ class AllocTracer : AllStatic {
   public:
     static void send_allocation_outside_tlab(Klass* klass, HeapWord* obj, size_t alloc_size, JavaThread* thread);
     static void send_allocation_in_new_tlab(Klass* klass, HeapWord* obj, size_t tlab_size, size_t alloc_size, JavaThread* thread);
+    static void send_allocation_sample(Klass* klass, HeapWord* obj, size_t alloc_size, size_t weight, bool large_allocation, JavaThread* thread);
     static void send_allocation_requiring_gc_event(size_t size, uint gcId);
 };
 

src/hotspot/share/gc/shared/memAllocator.cpp

@@ -30,6 +30,7 @@
 #include "gc/shared/memAllocator.hpp"
 #include "gc/shared/threadLocalAllocBuffer.inline.hpp"
 #include "gc/shared/tlab_globals.hpp"
+#include "jfr/jfrEvents.hpp"
 #include "memory/universe.hpp"
 #include "oops/arrayOop.hpp"
 #include "oops/oop.inline.hpp"
@@ -41,6 +42,7 @@
 #include "services/lowMemoryDetector.hpp"
 #include "utilities/align.hpp"
 #include "utilities/copy.hpp"
+#include "utilities/dtrace.hpp"
 #include "utilities/globalDefinitions.hpp"
 
 class MemAllocator::Allocation: StackObj {
@@ -52,7 +54,8 @@ class MemAllocator::Allocation: StackObj {
   bool                _overhead_limit_exceeded;
   bool                _allocated_outside_tlab;
   size_t              _allocated_tlab_size;
-  bool                _tlab_end_reset_for_sample;
+  bool                _tlab_end_reset_for_jvmti_sample;
+  bool                _tlab_end_reset_for_jfr_sample;
 
   bool check_out_of_memory();
   void verify_before();
@@ -76,7 +79,8 @@ class MemAllocator::Allocation: StackObj {
       _overhead_limit_exceeded(false),
       _allocated_outside_tlab(false),
       _allocated_tlab_size(0),
-      _tlab_end_reset_for_sample(false)
+      _tlab_end_reset_for_jvmti_sample(false),
+      _tlab_end_reset_for_jfr_sample(false)
   {
     assert(Thread::current() == allocator._thread, "do not pass MemAllocator across threads");
     verify_before();
@@ -171,7 +175,7 @@ void MemAllocator::Allocation::notify_allocation_jvmti_sampler() {
     return;
   }
 
-  if (!_allocated_outside_tlab && _allocated_tlab_size == 0 && !_tlab_end_reset_for_sample) {
+  if (!_allocated_outside_tlab && _allocated_tlab_size == 0 && !_tlab_end_reset_for_jvmti_sample) {
     // Sample if it's a non-TLAB allocation, or a TLAB allocation that either refills the TLAB
     // or expands it due to taking a sampler induced slow path.
     return;
@@ -181,23 +185,21 @@ void MemAllocator::Allocation::notify_allocation_jvmti_sampler() {
   // before doing the callback. The callback is done in the destructor of
   // the JvmtiSampledObjectAllocEventCollector.
   size_t bytes_since_last = 0;
-
+  size_t bytes_since_allocation = 0;
   {
     PreserveObj obj_h(_thread, _obj_ptr);
     JvmtiSampledObjectAllocEventCollector collector;
     size_t size_in_bytes = _allocator._word_size * HeapWordSize;
-    ThreadLocalAllocBuffer& tlab = _thread->tlab();
 
-    if (!_allocated_outside_tlab) {
-      bytes_since_last = tlab.bytes_since_last_sample_point();
+    if (_thread->heap_samplers().jvmti().check_for_sampling(&bytes_since_allocation, size_in_bytes, !_allocated_outside_tlab)) {
+      // HOTSPOT_GC_ALLOCOBJECT_SAMPLE(obj_h->klass()->name()->as_C_string(), size_in_bytes, bytes_since_allocation);
+      JvmtiExport::sampled_object_alloc_event_collector(obj_h());
     }
-
-    _thread->heap_sampler().check_for_sampling(obj_h(), size_in_bytes, bytes_since_last);
   }
 
-  if (_tlab_end_reset_for_sample || _allocated_tlab_size != 0) {
+  if (_tlab_end_reset_for_jvmti_sample || _allocated_tlab_size != 0) {
     // Tell tlab to forget bytes_since_last if we passed it to the heap sampler.
-    _thread->tlab().set_sample_end(bytes_since_last != 0);
+    _thread->tlab().set_jvmti_sample_end(!_allocated_outside_tlab);
   }
 }
 
@@ -217,6 +219,30 @@ void MemAllocator::Allocation::notify_allocation_jfr_sampler() {
     AllocTracer::send_allocation_in_new_tlab(obj()->klass(), mem, _allocated_tlab_size * HeapWordSize,
                                              size_in_bytes, _thread);
   }
+
+  EventObjectAllocationSample event;
+  if (!event.should_commit()) {
+    return;
+  }
+
+  bool hit_mark = _allocated_tlab_size != 0 || _tlab_end_reset_for_jfr_sample;
+  if (!_allocated_outside_tlab && !hit_mark) {
+    // Sample if it's a non-TLAB allocation, or a TLAB allocation that either refills the TLAB
+    // or expands it due to taking a sampler induced slow path.
+    return;
+  }
+
+  size_t bytes_since_allocation = 0;
+  if (_thread->heap_samplers().jfr().check_for_sampling(&bytes_since_allocation, size_in_bytes, !_allocated_outside_tlab)) {
+    size_t weight = bytes_since_allocation == 0 ? size_in_bytes : bytes_since_allocation;
+    AllocTracer::send_allocation_sample(obj()->klass(), mem, size_in_bytes, weight, _allocated_outside_tlab, _thread);
+    HOTSPOT_GC_ALLOCOBJECT_SAMPLE(obj()->klass()->name()->as_C_string(), size_in_bytes, weight);
+  }
+
+  if (hit_mark) {
+    // Tell tlab to forget bytes_since_last if we passed it to the heap sampler.
+    _thread->tlab().set_jfr_sample_end(!_allocated_outside_tlab);
+  }
 }
 
 void MemAllocator::Allocation::notify_allocation_dtrace_sampler() {
@@ -264,7 +290,7 @@ HeapWord* MemAllocator::mem_allocate_inside_tlab_slow(Allocation& allocation) co
 
     // We set back the allocation sample point to try to allocate this, reset it
     // when done.
-    allocation._tlab_end_reset_for_sample = true;
+    allocation._tlab_end_reset_for_jvmti_sample = true;
 
     if (mem != nullptr) {
       return mem;

src/hotspot/share/gc/shared/threadLocalAllocBuffer.cpp

@@ -50,7 +50,6 @@ ThreadLocalAllocBuffer::ThreadLocalAllocBuffer() :
   _desired_size(0),
   _refill_waste_limit(0),
   _allocated_before_last_gc(0),
-  _bytes_since_last_sample_point(0),
   _number_of_refills(0),
   _refill_waste(0),
   _gc_waste(0),
@@ -203,6 +202,7 @@ void ThreadLocalAllocBuffer::initialize(HeapWord* start,
   set_end(end);
   set_allocation_end(end);
   invariants();
+  _end_backup = nullptr;
 }
 
 void ThreadLocalAllocBuffer::initialize() {
@@ -313,21 +313,49 @@ void ThreadLocalAllocBuffer::print_stats(const char* tag) {
             _refill_waste * HeapWordSize);
 }
 
-void ThreadLocalAllocBuffer::set_sample_end(bool reset_byte_accumulation) {
+void ThreadLocalAllocBuffer::set_jvmti_sample_end(bool reset_byte_accumulation) {
+  ThreadHeapSampler& sampler = thread()->heap_samplers().jvmti();
   size_t heap_words_remaining = pointer_delta(_end, _top);
-  size_t bytes_until_sample = thread()->heap_sampler().bytes_until_sample();
+  size_t bytes_until_sample = sampler.bytes_until_sample();
   size_t words_until_sample = bytes_until_sample / HeapWordSize;
 
-  if (reset_byte_accumulation) {
-    _bytes_since_last_sample_point = 0;
+  if (heap_words_remaining > words_until_sample) {
+    HeapWord* new_end = _top + words_until_sample;
+    if (_end_backup != nullptr) {
+      if (new_end > _end_backup) {
+        HeapWord* tmp = new_end;
+        new_end = _end_backup;
+        _end_backup = tmp;
+      } else {
+        _end_backup = nullptr;
+      }
+    }
+    set_end(new_end);
+    sampler.update_bytes(bytes_until_sample, reset_byte_accumulation);
+  } else {
+    sampler.update_bytes(heap_words_remaining * HeapWordSize, reset_byte_accumulation);
   }
+}
+
+void ThreadLocalAllocBuffer::set_jfr_sample_end(bool reset_byte_accumulation) {
+  ThreadHeapSampler& sampler = thread()->heap_samplers().jfr();
+  size_t heap_words_remaining = pointer_delta(_end, _top);
+  size_t bytes_until_sample = sampler.bytes_until_sample();
+  size_t words_until_sample = bytes_until_sample / HeapWordSize;
 
   if (heap_words_remaining > words_until_sample) {
     HeapWord* new_end = _top + words_until_sample;
+    if (_end_backup != nullptr) {
+      if (new_end > _end_backup) {
+        HeapWord* tmp = new_end;
+        new_end = _end_backup;
+        _end_backup = tmp;
+      }
+    }
     set_end(new_end);
-    _bytes_since_last_sample_point += bytes_until_sample;
+    sampler.update_bytes(bytes_until_sample, reset_byte_accumulation);
   } else {
-    _bytes_since_last_sample_point += heap_words_remaining * HeapWordSize;
+    sampler.update_bytes(heap_words_remaining * HeapWordSize, reset_byte_accumulation);
   }
 }
 

src/hotspot/share/gc/shared/threadLocalAllocBuffer.hpp

@@ -51,12 +51,12 @@ class ThreadLocalAllocBuffer: public CHeapObj<mtThread> {
   HeapWord* _top;                                // address after last allocation
   HeapWord* _pf_top;                             // allocation prefetch watermark
   HeapWord* _end;                                // allocation end (can be the sampling end point or _allocation_end)
+  HeapWord* _end_backup;                         // backup of _end for interleaved jvmti and jfr sampling
   HeapWord* _allocation_end;                     // end for allocations (actual TLAB end, excluding alignment_reserve)
 
   size_t    _desired_size;                       // desired size   (including alignment_reserve)
   size_t    _refill_waste_limit;                 // hold onto tlab if free() is larger than this
   size_t    _allocated_before_last_gc;           // total bytes allocated up until the last gc
-  size_t    _bytes_since_last_sample_point;      // bytes since last sample point.
 
   static size_t   _max_size;                          // maximum size of any TLAB
   static int      _reserve_for_allocation_prefetch;   // Reserve at the end of the TLAB
@@ -124,7 +124,6 @@ class ThreadLocalAllocBuffer: public CHeapObj<mtThread> {
   size_t free() const                            { return pointer_delta(end(), top()); }
   // Don't discard tlab if remaining space is larger than this.
   size_t refill_waste_limit() const              { return _refill_waste_limit; }
-  size_t bytes_since_last_sample_point() const   { return _bytes_since_last_sample_point; }
 
   // For external inspection.
   const HeapWord* start_relaxed() const;
@@ -168,7 +167,8 @@ class ThreadLocalAllocBuffer: public CHeapObj<mtThread> {
   void initialize();
 
   void set_back_allocation_end();
-  void set_sample_end(bool reset_byte_accumulation);
+  void set_jvmti_sample_end(bool reset_byte_accumulation);
+  void set_jfr_sample_end(bool reset_byte_accumulation);
 
   static size_t refill_waste_limit_increment();
 

src/hotspot/share/jfr/recorder/service/jfrEventThrottler.cpp

@@ -27,6 +27,7 @@
 #include "jfr/recorder/service/jfrEventThrottler.hpp"
 #include "jfr/utilities/jfrSpinlockHelper.hpp"
 #include "logging/log.hpp"
+#include "runtime/threadHeapSampler.hpp"
 
 constexpr static const JfrSamplerParams _disabled_params = {
                                                              0, // sample points per window
@@ -72,6 +73,9 @@ void JfrEventThrottler::configure(JfrEventId event_id, int64_t sample_size, int6
   }
   assert(_throttler != nullptr, "JfrEventThrottler has not been properly initialized");
   _throttler->configure(sample_size, period_ms);
+
+  // TODO: Hack to get the allocation sampler going
+  ThreadHeapSamplers::set_jfr_sampling_interval(512 * 1024);
 }
 
 /*

src/hotspot/share/prims/jvmtiEnv.cpp

@@ -3760,7 +3760,7 @@ JvmtiEnv::SetHeapSamplingInterval(jint sampling_interval) {
   if (sampling_interval < 0) {
     return JVMTI_ERROR_ILLEGAL_ARGUMENT;
   }
-  ThreadHeapSampler::set_sampling_interval(sampling_interval);
+  ThreadHeapSamplers::set_jvmti_sampling_interval(sampling_interval);
   return JVMTI_ERROR_NONE;
 } /* end SetHeapSamplingInterval */
 

src/hotspot/share/runtime/thread.cpp

@@ -64,7 +64,7 @@ THREAD_LOCAL Thread* Thread::_thr_current = nullptr;
 
 DEBUG_ONLY(Thread* Thread::_starting_thread = nullptr;)
 
-Thread::Thread(MEMFLAGS flags) {
+Thread::Thread(MEMFLAGS flags) : _heap_samplers(&_tlab) {
 
   DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
 

src/hotspot/share/runtime/thread.hpp

@@ -267,7 +267,7 @@ class Thread: public ThreadShadow {
   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
                                                 // the Java heap
-  ThreadHeapSampler _heap_sampler;              // For use when sampling the memory.
+  ThreadHeapSamplers _heap_samplers;            // Used by the JVMTI allocation sampler
 
   ThreadStatisticalInfo _statistical_info;      // Statistics about the thread
 
@@ -418,7 +418,7 @@ class Thread: public ThreadShadow {
   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
   inline jlong cooked_allocated_bytes();
 
-  ThreadHeapSampler& heap_sampler()     { return _heap_sampler; }
+  ThreadHeapSamplers& heap_samplers()  { return _heap_samplers; }
 
   ThreadStatisticalInfo& statistical_info() { return _statistical_info; }