Allocation sampling for paged/lo spaces

src/profiler/sampling-heap-profiler.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/profiler/sampling-heap-profiler.h"
 
 #include <stdint.h>
 #include <memory>
 #include "src/api.h"
 #include "src/base/utils/random-number-generator.h"
 #include "src/frames-inl.h"
 #include "src/heap/heap.h"
 #include "src/isolate.h"
 #include "src/profiler/strings-storage.h"
 
 namespace v8 {
 namespace internal {
 
+// We sample with a Poisson process, with constant average sampling interval.
+// This follows the exponential probability distribution with parameter
+// λ = 1/rate where rate is the average number of bytes between samples.
+//
+// Let u be a uniformly distributed random number between 0 and 1, then
+// next_sample = (- ln u) / λ
+intptr_t SamplingAllocationObserver::GetNextSampleInterval(
+    base::RandomNumberGenerator* random, uint64_t rate) {
+  if (FLAG_sampling_heap_profiler_suppress_randomness) {
+    return rate;
+  }
+  double u = random->NextDouble();
+  double next = (-std::log(u)) * rate;
+  return next < kPointerSize
+             ? kPointerSize
+             : (next > INT_MAX ? INT_MAX : static_cast<intptr_t>(next));
+}
+
 SamplingHeapProfiler::SamplingHeapProfiler(Heap* heap, StringsStorage* names,
                                            uint64_t rate, int stack_depth)
-    : InlineAllocationObserver(GetNextSampleInterval(
-          heap->isolate()->random_number_generator(), rate)),
-      isolate_(heap->isolate()),
+    : isolate_(heap->isolate()),
       heap_(heap),
-      random_(isolate_->random_number_generator()),
       names_(names),
       samples_(),
-      rate_(rate),
       stack_depth_(stack_depth) {
-  heap->new_space()->AddInlineAllocationObserver(this);
+  new_space_observer_ = new SamplingAllocationObserver(

[ofrobots, 2016/02/11 05:51:46]

This allocation is never freed so it will leak. Use v8::base::SmartPointer to
manage this pointer.

[mattloring, 2016/02/11 14:54:14]

Done.

+      heap_, rate, rate, this, heap->isolate()->random_number_generator());
+  heap->new_space()->AddAllocationObserver(new_space_observer_);
+  other_spaces_observer_ = new SamplingAllocationObserver(

[ofrobots, 2016/02/11 05:51:47]

likewise.

[mattloring, 2016/02/11 14:54:14]

Done.

+      heap_, rate, rate, this, heap->isolate()->random_number_generator());
+  AllSpaces spaces(heap);
+  for (Space* space = spaces.next(); space != NULL; space = spaces.next()) {
+    if (space != heap->new_space()) {
+      space->AddAllocationObserver(other_spaces_observer_);
+    }
+  }
 }
 
 
 SamplingHeapProfiler::~SamplingHeapProfiler() {
-  heap_->new_space()->RemoveInlineAllocationObserver(this);
+  heap_->new_space()->RemoveAllocationObserver(new_space_observer_);
+  AllSpaces spaces(heap_);
+  for (Space* space = spaces.next(); space != NULL; space = spaces.next()) {
+    if (space != heap_->new_space()) {
+      space->RemoveAllocationObserver(other_spaces_observer_);
+    }
+  }
 
   // Clear samples and drop all the weak references we are keeping.
   std::set<SampledAllocation*>::iterator it;
   for (it = samples_.begin(); it != samples_.end(); ++it) {
     delete *it;
   }
   std::set<SampledAllocation*> empty;
   samples_.swap(empty);
 }
 
-void SamplingHeapProfiler::Step(int bytes_allocated, Address soon_object,
-                                size_t size) {
-  DCHECK(heap_->gc_state() == Heap::NOT_IN_GC);
-  DCHECK(soon_object);
-  SampleObject(soon_object, size);
-}
-
 
 void SamplingHeapProfiler::SampleObject(Address soon_object, size_t size) {
   DisallowHeapAllocation no_allocation;
 
   HandleScope scope(isolate_);
   HeapObject* heap_object = HeapObject::FromAddress(soon_object);
   Handle<Object> obj(heap_object, isolate_);
 
   // Mark the new block as FreeSpace to make sure the heap is iterable while we
   // are taking the sample.
   heap()->CreateFillerObjectAt(soon_object, static_cast<int>(size));
 
   Local<v8::Value> loc = v8::Utils::ToLocal(obj);
 
   SampledAllocation* sample =
       new SampledAllocation(this, isolate_, loc, size, stack_depth_);
   samples_.insert(sample);
 }
 
 
-// We sample with a Poisson process, with constant average sampling interval.
-// This follows the exponential probability distribution with parameter
-// λ = 1/rate where rate is the average number of bytes between samples.
-//
-// Let u be a uniformly distributed random number between 0 and 1, then
-// next_sample = (- ln u) / λ
-intptr_t SamplingHeapProfiler::GetNextSampleInterval(
-    base::RandomNumberGenerator* random, uint64_t rate) {
-  if (FLAG_sampling_heap_profiler_suppress_randomness) {
-    return rate;
-  }
-  double u = random->NextDouble();
-  double next = (-std::log(u)) * rate;
-  return next < kPointerSize
-             ? kPointerSize
-             : (next > INT_MAX ? INT_MAX : static_cast<intptr_t>(next));
-}
-
-
 void SamplingHeapProfiler::SampledAllocation::OnWeakCallback(
     const WeakCallbackInfo<SampledAllocation>& data) {
   SampledAllocation* sample = data.GetParameter();
   sample->sampling_heap_profiler_->samples_.erase(sample);
   delete sample;
 }
 
 
 SamplingHeapProfiler::FunctionInfo::FunctionInfo(SharedFunctionInfo* shared,
                                                  StringsStorage* names)
@@ skipping 50 matching lines @@
         name = "(IDLE)";
         break;
       case JS:
         name = "(JS)";
         break;
     }
     stack_.push_back(new FunctionInfo(name));
   }
 }
 
-
-SamplingHeapProfiler::Node* SamplingHeapProfiler::AllocateNode(
+v8::AllocationProfile::Node* SamplingHeapProfiler::AllocateNode(
     AllocationProfile* profile, const std::map<int, Script*>& scripts,
     FunctionInfo* function_info) {
   DCHECK(function_info->get_name());
   DCHECK(function_info->get_script_name());
 
   int line = v8::AllocationProfile::kNoLineNumberInfo;
   int column = v8::AllocationProfile::kNoColumnNumberInfo;
 
   if (function_info->get_script_id() != v8::UnboundScript::kNoScriptId) {
     // Cannot use std::map<T>::at because it is not available on android.
     auto non_const_scripts = const_cast<std::map<int, Script*>&>(scripts);
     Handle<Script> script(non_const_scripts[function_info->get_script_id()]);
 
     line =
         1 + Script::GetLineNumber(script, function_info->get_start_position());
     column = 1 + Script::GetColumnNumber(script,
                                          function_info->get_start_position());
   }
 
-  profile->nodes().push_back(
-      Node({ToApiHandle<v8::String>(isolate_->factory()->InternalizeUtf8String(
-                function_info->get_name())),
-            ToApiHandle<v8::String>(isolate_->factory()->InternalizeUtf8String(
-                function_info->get_script_name())),
-            function_info->get_script_id(), function_info->get_start_position(),
-            line, column, std::vector<Node*>(),
-            std::vector<v8::AllocationProfile::Allocation>()}));
+  profile->nodes().push_back(v8::AllocationProfile::Node(
+      {ToApiHandle<v8::String>(isolate_->factory()->InternalizeUtf8String(
+           function_info->get_name())),
+       ToApiHandle<v8::String>(isolate_->factory()->InternalizeUtf8String(
+           function_info->get_script_name())),
+       function_info->get_script_id(), function_info->get_start_position(),
+       line, column, std::vector<v8::AllocationProfile::Node*>(),
+       std::vector<v8::AllocationProfile::Allocation>()}));
 
   return &profile->nodes().back();
 }
 
-
-SamplingHeapProfiler::Node* SamplingHeapProfiler::FindOrAddChildNode(
+v8::AllocationProfile::Node* SamplingHeapProfiler::FindOrAddChildNode(
     AllocationProfile* profile, const std::map<int, Script*>& scripts,
-    Node* parent, FunctionInfo* function_info) {
-  for (Node* child : parent->children) {
+    v8::AllocationProfile::Node* parent, FunctionInfo* function_info) {
+  for (v8::AllocationProfile::Node* child : parent->children) {
     if (child->script_id == function_info->get_script_id() &&
         child->start_position == function_info->get_start_position())
       return child;
   }
-  Node* child = AllocateNode(profile, scripts, function_info);
+  v8::AllocationProfile::Node* child =
+      AllocateNode(profile, scripts, function_info);
   parent->children.push_back(child);
   return child;
 }
 
-
-SamplingHeapProfiler::Node* SamplingHeapProfiler::AddStack(
+v8::AllocationProfile::Node* SamplingHeapProfiler::AddStack(
     AllocationProfile* profile, const std::map<int, Script*>& scripts,
     const std::vector<FunctionInfo*>& stack) {
-  Node* node = profile->GetRootNode();
+  v8::AllocationProfile::Node* node = profile->GetRootNode();
 
   // We need to process the stack in reverse order as the top of the stack is
   // the first element in the list.
   for (auto it = stack.rbegin(); it != stack.rend(); ++it) {
     FunctionInfo* function_info = *it;
     node = FindOrAddChildNode(profile, scripts, node, function_info);
   }
   return node;
 }
 
@@ skipping 10 matching lines @@
     }
   }
 
   auto profile = new v8::internal::AllocationProfile();
 
   // Create the root node.
   FunctionInfo function_info("(root)");
   AllocateNode(profile, scripts, &function_info);
 
   for (SampledAllocation* allocation : samples_) {
-    Node* node = AddStack(profile, scripts, allocation->get_stack());
+    v8::AllocationProfile::Node* node =
+        AddStack(profile, scripts, allocation->get_stack());
     node->allocations.push_back({allocation->get_size(), 1});
   }
 
   return profile;
 }
 
 
 }  // namespace internal
 }  // namespace v8