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>

8 files changed, 355 insertions, 74 deletions

diff --git a/lib/internal/histogram.js b/lib/internal/histogram.js
new file mode 100644
index 0000000000..6deb8314a4
--- /dev/null
+++ b/lib/internal/histogram.js
@@ -0,0 +1,94 @@
+'use strict';
+
+const {
+  customInspectSymbol: kInspect,
+} = require('internal/util');
+
+const { format } = require('util');
+const { Map, Symbol } = primordials;
+
+const {
+  ERR_INVALID_ARG_TYPE,
+  ERR_INVALID_ARG_VALUE,
+} = require('internal/errors').codes;
+
+const kDestroy = Symbol('kDestroy');
+const kHandle = Symbol('kHandle');
+
+// Histograms are created internally by Node.js and used to
+// record various metrics. This Histogram class provides a
+// generally read-only view of the internal histogram.
+class Histogram {
+  #handle = undefined;
+  #map = new Map();
+
+  constructor(internal) {
+    this.#handle = internal;
+  }
+
+  [kInspect]() {
+    const obj = {
+      min: this.min,
+      max: this.max,
+      mean: this.mean,
+      exceeds: this.exceeds,
+      stddev: this.stddev,
+      percentiles: this.percentiles,
+    };
+    return `Histogram ${format(obj)}`;
+  }
+
+  get min() {
+    return this.#handle ? this.#handle.min() : undefined;
+  }
+
+  get max() {
+    return this.#handle ? this.#handle.max() : undefined;
+  }
+
+  get mean() {
+    return this.#handle ? this.#handle.mean() : undefined;
+  }
+
+  get exceeds() {
+    return this.#handle ? this.#handle.exceeds() : undefined;
+  }
+
+  get stddev() {
+    return this.#handle ? this.#handle.stddev() : undefined;
+  }
+
+  percentile(percentile) {
+    if (typeof percentile !== 'number')
+      throw new ERR_INVALID_ARG_TYPE('percentile', 'number', percentile);
+
+    if (percentile <= 0 || percentile > 100)
+      throw new ERR_INVALID_ARG_VALUE.RangeError('percentile', percentile);
+
+    return this.#handle ? this.#handle.percentile(percentile) : undefined;
+  }
+
+  get percentiles() {
+    this.#map.clear();
+    if (this.#handle)
+      this.#handle.percentiles(this.#map);
+    return this.#map;
+  }
+
+  reset() {
+    if (this.#handle)
+      this.#handle.reset();
+  }
+
+  [kDestroy]() {
+    this.#handle = undefined;
+  }
+
+  get [kHandle]() { return this.#handle; }
+}
+
+module.exports = {
+  Histogram,
+  kDestroy,
+  kHandle,
+};
diff --git a/lib/perf_hooks.js b/lib/perf_hooks.js
index 267b4577ff..a141705728 100644
--- a/lib/perf_hooks.js
+++ b/lib/perf_hooks.js
@@ -3,7 +3,6 @@
 const {
   ArrayIsArray,
   Boolean,
-  Map,
   NumberIsSafeInteger,
   ObjectDefineProperties,
   ObjectDefineProperty,
@@ -52,16 +51,18 @@ const kInspect = require('internal/util').customInspectSymbol;
 
 const {
   ERR_INVALID_CALLBACK,
-  ERR_INVALID_ARG_VALUE,
   ERR_INVALID_ARG_TYPE,
   ERR_INVALID_OPT_VALUE,
   ERR_VALID_PERFORMANCE_ENTRY_TYPE,
   ERR_INVALID_PERFORMANCE_MARK
 } = require('internal/errors').codes;
 
+const {
+  Histogram,
+  kHandle,
+} = require('internal/histogram');
+
 const { setImmediate } = require('timers');
-const kHandle = Symbol('handle');
-const kMap = Symbol('map');
 const kCallback = Symbol('callback');
 const kTypes = Symbol('types');
 const kEntries = Symbol('entries');
@@ -557,47 +558,9 @@ function sortedInsert(list, entry) {
   list.splice(location, 0, entry);
 }
 
-class ELDHistogram {
-  constructor(handle) {
-    this[kHandle] = handle;
-    this[kMap] = new Map();
-  }
-
-  reset() { this[kHandle].reset(); }
+class ELDHistogram extends Histogram {
   enable() { return this[kHandle].enable(); }
   disable() { return this[kHandle].disable(); }
-
-  get exceeds() { return this[kHandle].exceeds(); }
-  get min() { return this[kHandle].min(); }
-  get max() { return this[kHandle].max(); }
-  get mean() { return this[kHandle].mean(); }
-  get stddev() { return this[kHandle].stddev(); }
-  percentile(percentile) {
-    if (typeof percentile !== 'number') {
-      throw new ERR_INVALID_ARG_TYPE('percentile', 'number', percentile);
-    }
-    if (percentile <= 0 || percentile > 100) {
-      throw new ERR_INVALID_ARG_VALUE.RangeError('percentile',
-                                                 percentile);
-    }
-    return this[kHandle].percentile(percentile);
-  }
-  get percentiles() {
-    this[kMap].clear();
-    this[kHandle].percentiles(this[kMap]);
-    return this[kMap];
-  }
-
-  [kInspect]() {
-    return {
-      min: this.min,
-      max: this.max,
-      mean: this.mean,
-      stddev: this.stddev,
-      percentiles: this.percentiles,
-      exceeds: this.exceeds
-    };
-  }
 }
 
 function monitorEventLoopDelay(options = {}) {
diff --git a/node.gyp b/node.gyp
index 9c632d3838..b941eff565 100644
--- a/node.gyp
+++ b/node.gyp
@@ -141,6 +141,7 @@
       'lib/internal/fs/watchers.js',
       'lib/internal/http.js',
       'lib/internal/heap_utils.js',
+      'lib/internal/histogram.js',
       'lib/internal/idna.js',
       'lib/internal/inspector_async_hook.js',
       'lib/internal/js_stream_socket.js',
@@ -534,6 +535,7 @@
         'src/fs_event_wrap.cc',
         'src/handle_wrap.cc',
         'src/heap_utils.cc',
+        'src/histogram.cc',
         'src/js_native_api.h',
         'src/js_native_api_types.h',
         'src/js_native_api_v8.cc',
diff --git a/src/env.h b/src/env.h
index 3b577e4030..f02c8e9775 100644
--- a/src/env.h
+++ b/src/env.h
@@ -406,6 +406,7 @@ constexpr size_t kFsStatsBufferLength =
   V(filehandlereadwrap_template, v8::ObjectTemplate)                           \
   V(fsreqpromise_constructor_template, v8::ObjectTemplate)                     \
   V(handle_wrap_ctor_template, v8::FunctionTemplate)                           \
+  V(histogram_instance_template, v8::ObjectTemplate)                           \
   V(http2settings_constructor_template, v8::ObjectTemplate)                    \
   V(http2stream_constructor_template, v8::ObjectTemplate)                      \
   V(http2ping_constructor_template, v8::ObjectTemplate)                        \
diff --git a/src/histogram-inl.h b/src/histogram-inl.h
index 3135041f73..58911dae8f 100644
--- a/src/histogram-inl.h
+++ b/src/histogram-inl.h
@@ -4,58 +4,78 @@
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
 #include "histogram.h"
+#include "base_object-inl.h"
 #include "node_internals.h"
 
 namespace node {
 
-inline Histogram::Histogram(int64_t lowest, int64_t highest, int figures) {
-  CHECK_EQ(0, hdr_init(lowest, highest, figures, &histogram_));
+void Histogram::Reset() {
+  hdr_reset(histogram_.get());
 }
 
-inline Histogram::~Histogram() {
-  hdr_close(histogram_);
+bool Histogram::Record(int64_t value) {
+  return hdr_record_value(histogram_.get(), value);
 }
 
-inline void Histogram::Reset() {
-  hdr_reset(histogram_);
+int64_t Histogram::Min() {
+  return hdr_min(histogram_.get());
 }
 
-inline bool Histogram::Record(int64_t value) {
-  return hdr_record_value(histogram_, value);
+int64_t Histogram::Max() {
+  return hdr_max(histogram_.get());
 }
 
-inline int64_t Histogram::Min() {
-  return hdr_min(histogram_);
+double Histogram::Mean() {
+  return hdr_mean(histogram_.get());
 }
 
-inline int64_t Histogram::Max() {
-  return hdr_max(histogram_);
+double Histogram::Stddev() {
+  return hdr_stddev(histogram_.get());
 }
 
-inline double Histogram::Mean() {
-  return hdr_mean(histogram_);
-}
-
-inline double Histogram::Stddev() {
-  return hdr_stddev(histogram_);
-}
-
-inline double Histogram::Percentile(double percentile) {
+double Histogram::Percentile(double percentile) {
   CHECK_GT(percentile, 0);
   CHECK_LE(percentile, 100);
-  return hdr_value_at_percentile(histogram_, percentile);
+  return static_cast<double>(
+      hdr_value_at_percentile(histogram_.get(), percentile));
 }
 
-inline void Histogram::Percentiles(std::function<void(double, double)> fn) {
+template <typename Iterator>
+void Histogram::Percentiles(Iterator&& fn) {
   hdr_iter iter;
-  hdr_iter_percentile_init(&iter, histogram_, 1);
+  hdr_iter_percentile_init(&iter, histogram_.get(), 1);
   while (hdr_iter_next(&iter)) {
     double key = iter.specifics.percentiles.percentile;
-    double value = iter.value;
+    double value = static_cast<double>(iter.value);
     fn(key, value);
   }
 }
 
+bool HistogramBase::RecordDelta() {
+  uint64_t time = uv_hrtime();
+  bool ret = true;
+  if (prev_ > 0) {
+    int64_t delta = time - prev_;
+    if (delta > 0) {
+      ret = Record(delta);
+      TraceDelta(delta);
+      if (!ret) {
+        if (exceeds_ < 0xFFFFFFFF)
+          exceeds_++;
+        TraceExceeds(delta);
+      }
+    }
+  }
+  prev_ = time;
+  return ret;
+}
+
+void HistogramBase::ResetState() {
+  Reset();
+  exceeds_ = 0;
+  prev_ = 0;
+}
+
 }  // namespace node
 
 #endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
diff --git a/src/histogram.cc b/src/histogram.cc
new file mode 100644
index 0000000000..8d1eb77b1b
--- /dev/null
+++ b/src/histogram.cc
@@ -0,0 +1,141 @@
+#include "histogram.h"  // NOLINT(build/include_inline)
+#include "histogram-inl.h"
+#include "memory_tracker-inl.h"
+
+namespace node {
+
+using v8::FunctionCallbackInfo;
+using v8::FunctionTemplate;
+using v8::Local;
+using v8::Map;
+using v8::Number;
+using v8::ObjectTemplate;
+using v8::String;
+using v8::Value;
+
+Histogram::Histogram(int64_t lowest, int64_t highest, int figures) {
+  hdr_histogram* histogram;
+  CHECK_EQ(0, hdr_init(lowest, highest, figures, &histogram));
+  histogram_.reset(histogram);
+}
+
+HistogramBase::HistogramBase(
+    Environment* env,
+    v8::Local<v8::Object> wrap,
+    int64_t lowest,
+    int64_t highest,
+    int figures)
+    : BaseObject(env, wrap),
+      Histogram(lowest, highest, figures) {
+  MakeWeak();
+}
+
+void HistogramBase::MemoryInfo(MemoryTracker* tracker) const {
+  tracker->TrackFieldWithSize("histogram", GetMemorySize());
+}
+
+void HistogramBase::GetMin(const FunctionCallbackInfo<Value>& args) {
+  HistogramBase* histogram;
+  ASSIGN_OR_RETURN_UNWRAP(&histogram, args.Holder());
+  double value = static_cast<double>(histogram->Min());
+  args.GetReturnValue().Set(value);
+}
+
+void HistogramBase::GetMax(const FunctionCallbackInfo<Value>& args) {
+  HistogramBase* histogram;
+  ASSIGN_OR_RETURN_UNWRAP(&histogram, args.Holder());
+  double value = static_cast<double>(histogram->Max());
+  args.GetReturnValue().Set(value);
+}
+
+void HistogramBase::GetMean(const FunctionCallbackInfo<Value>& args) {
+  HistogramBase* histogram;
+  ASSIGN_OR_RETURN_UNWRAP(&histogram, args.Holder());
+  args.GetReturnValue().Set(histogram->Mean());
+}
+
+void HistogramBase::GetExceeds(const FunctionCallbackInfo<Value>& args) {
+  HistogramBase* histogram;
+  ASSIGN_OR_RETURN_UNWRAP(&histogram, args.Holder());
+  double value = static_cast<double>(histogram->Exceeds());
+  args.GetReturnValue().Set(value);
+}
+
+void HistogramBase::GetStddev(const FunctionCallbackInfo<Value>& args) {
+  HistogramBase* histogram;
+  ASSIGN_OR_RETURN_UNWRAP(&histogram, args.Holder());
+  args.GetReturnValue().Set(histogram->Stddev());
+}
+
+void HistogramBase::GetPercentile(
+    const FunctionCallbackInfo<Value>& args) {
+  HistogramBase* histogram;
+  ASSIGN_OR_RETURN_UNWRAP(&histogram, args.Holder());
+  CHECK(args[0]->IsNumber());
+  double percentile = args[0].As<Number>()->Value();
+  args.GetReturnValue().Set(histogram->Percentile(percentile));
+}
+
+void HistogramBase::GetPercentiles(
+    const FunctionCallbackInfo<Value>& args) {
+  Environment* env = Environment::GetCurrent(args);
+  HistogramBase* histogram;
+  ASSIGN_OR_RETURN_UNWRAP(&histogram, args.Holder());
+  CHECK(args[0]->IsMap());
+  Local<Map> map = args[0].As<Map>();
+  histogram->Percentiles([map, env](double key, double value) {
+    map->Set(
+        env->context(),
+        Number::New(env->isolate(), key),
+        Number::New(env->isolate(), value)).IsEmpty();
+  });
+}
+
+void HistogramBase::DoReset(const FunctionCallbackInfo<Value>& args) {
+  HistogramBase* histogram;
+  ASSIGN_OR_RETURN_UNWRAP(&histogram, args.Holder());
+  histogram->ResetState();
+}
+
+BaseObjectPtr<HistogramBase> HistogramBase::New(
+    Environment* env,
+    int64_t lowest,
+    int64_t highest,
+    int figures) {
+  CHECK_LE(lowest, highest);
+  CHECK_GT(figures, 0);
+  v8::Local<v8::Object> obj;
+  auto tmpl = env->histogram_instance_template();
+  if (!tmpl->NewInstance(env->context()).ToLocal(&obj))
+    return {};
+
+  return MakeDetachedBaseObject<HistogramBase>(
+      env, obj, lowest, highest, figures);
+}
+
+void HistogramBase::Initialize(Environment* env) {
+  // Guard against multiple initializations
+  if (!env->histogram_instance_template().IsEmpty())
+    return;
+
+  Local<FunctionTemplate> histogram = FunctionTemplate::New(env->isolate());
+  Local<String> classname = FIXED_ONE_BYTE_STRING(env->isolate(), "Histogram");
+  histogram->SetClassName(classname);
+
+  Local<ObjectTemplate> histogramt =
+    histogram->InstanceTemplate();
+
+  histogramt->SetInternalFieldCount(1);
+  env->SetProtoMethod(histogram, "exceeds", HistogramBase::GetExceeds);
+  env->SetProtoMethod(histogram, "min", HistogramBase::GetMin);
+  env->SetProtoMethod(histogram, "max", HistogramBase::GetMax);
+  env->SetProtoMethod(histogram, "mean", HistogramBase::GetMean);
+  env->SetProtoMethod(histogram, "stddev", HistogramBase::GetStddev);
+  env->SetProtoMethod(histogram, "percentile", HistogramBase::GetPercentile);
+  env->SetProtoMethod(histogram, "percentiles", HistogramBase::GetPercentiles);
+  env->SetProtoMethod(histogram, "reset", HistogramBase::DoReset);
+
+  env->set_histogram_instance_template(histogramt);
+}
+
+}  // namespace node
diff --git a/src/histogram.h b/src/histogram.h
index eb94af5da2..e92c31c472 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
diff --git a/src/node_perf.h b/src/node_perf.h
index 4f5ca93f22..ac65533a77 100644
--- a/src/node_perf.h
+++ b/src/node_perf.h
@@ -161,7 +161,7 @@ class ELDHistogram : public HandleWrap, public Histogram {
     exceeds_ = 0;
     prev_ = 0;
   }
-  int64_t Exceeds() { return exceeds_; }
+  int64_t Exceeds() const { return exceeds_; }
 
   void MemoryInfo(MemoryTracker* tracker) const override {
     tracker->TrackFieldWithSize("histogram", GetMemorySize());