perf,src: add HistogramBase and internal/histogram.js

Separating this out from the QUIC PR to allow it to be separately
reviewed. The QUIC implementation makes use of the hdr_histogram
for dynamic performance monitoring. This introduces a BaseObject
class that allows the internal histograms to be accessed on the
JavaScript side and adds a generic Histogram class that will be
used by both QUIC and perf_hooks (for the event loop delay
monitoring).

Signed-off-by: James M Snell <jasnell@gmail.com>

PR-URL: https://github.com/nodejs/node/pull/31988
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

1 files changed, 65 insertions, 5 deletions

diff --git a/src/histogram.h b/src/histogram.h
index eb94af5da2a..e92c31c4724 100644
--- a/src/histogram.h
+++ b/src/histogram.h
@@ -4,15 +4,24 @@
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
 #include "hdr_histogram.h"
+#include "base_object.h"
+#include "util.h"
+
 #include <functional>
+#include <limits>
 #include <map>
 
 namespace node {
 
+constexpr int kDefaultHistogramFigures = 3;
+
 class Histogram {
  public:
-  inline Histogram(int64_t lowest, int64_t highest, int figures = 3);
-  inline virtual ~Histogram();
+  Histogram(
+      int64_t lowest = std::numeric_limits<int64_t>::min(),
+      int64_t highest = std::numeric_limits<int64_t>::max(),
+      int figures = kDefaultHistogramFigures);
+  virtual ~Histogram() = default;
 
   inline bool Record(int64_t value);
   inline void Reset();
@@ -21,14 +30,65 @@ class Histogram {
   inline double Mean();
   inline double Stddev();
   inline double Percentile(double percentile);
-  inline void Percentiles(std::function<void(double, double)> fn);
+
+  // Iterator is a function type that takes two doubles as argument, one for
+  // percentile and one for the value at that percentile.
+  template <typename Iterator>
+  inline void Percentiles(Iterator&& fn);
 
   size_t GetMemorySize() const {
-    return hdr_get_memory_size(histogram_);
+    return hdr_get_memory_size(histogram_.get());
   }
 
  private:
-  hdr_histogram* histogram_;
+  using HistogramPointer = DeleteFnPtr<hdr_histogram, hdr_close>;
+  HistogramPointer histogram_;
+};
+
+class HistogramBase : public BaseObject, public Histogram {
+ public:
+  virtual ~HistogramBase() = default;
+
+  virtual void TraceDelta(int64_t delta) {}
+  virtual void TraceExceeds(int64_t delta) {}
+
+  inline bool RecordDelta();
+  inline void ResetState();
+
+  int64_t Exceeds() const { return exceeds_; }
+
+  void MemoryInfo(MemoryTracker* tracker) const override;
+  SET_MEMORY_INFO_NAME(HistogramBase)
+  SET_SELF_SIZE(HistogramBase)
+
+  static void GetMin(const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void GetMax(const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void GetMean(const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void GetExceeds(const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void GetStddev(const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void GetPercentile(
+      const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void GetPercentiles(
+      const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void DoReset(const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void Initialize(Environment* env);
+
+  static BaseObjectPtr<HistogramBase> New(
+      Environment* env,
+      int64_t lowest = std::numeric_limits<int64_t>::min(),
+      int64_t highest = std::numeric_limits<int64_t>::max(),
+      int figures = kDefaultHistogramFigures);
+
+  HistogramBase(
+      Environment* env,
+      v8::Local<v8::Object> wrap,
+      int64_t lowest = std::numeric_limits<int64_t>::min(),
+      int64_t highest = std::numeric_limits<int64_t>::max(),
+      int figures = kDefaultHistogramFigures);
+
+ private:
+  int64_t exceeds_ = 0;
+  uint64_t prev_ = 0;
 };
 
 }  // namespace node