1 files changed, 144 insertions, 0 deletions
diff --git a/src/rocksdb/monitoring/statistics.h b/src/rocksdb/monitoring/statistics.h
new file mode 100644
index 000000000..e0dc29d28
--- /dev/null
+++ b/src/rocksdb/monitoring/statistics.h
@@ -0,0 +1,144 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+#pragma once
+#include <atomic>
+#include <map>
+#include <string>
+#include <vector>
+
+#include "monitoring/histogram.h"
+#include "port/likely.h"
+#include "port/port.h"
+#include "rocksdb/statistics.h"
+#include "util/core_local.h"
+#include "util/mutexlock.h"
+
+#ifdef __clang__
+#define ROCKSDB_FIELD_UNUSED __attribute__((__unused__))
+#else
+#define ROCKSDB_FIELD_UNUSED
+#endif  // __clang__
+
+#ifndef STRINGIFY
+#define STRINGIFY(x) #x
+#define TOSTRING(x) STRINGIFY(x)
+#endif
+
+namespace ROCKSDB_NAMESPACE {
+
+enum TickersInternal : uint32_t {
+  INTERNAL_TICKER_ENUM_START = TICKER_ENUM_MAX,
+  INTERNAL_TICKER_ENUM_MAX
+};
+
+enum HistogramsInternal : uint32_t {
+  INTERNAL_HISTOGRAM_START = HISTOGRAM_ENUM_MAX,
+  INTERNAL_HISTOGRAM_ENUM_MAX
+};
+
+class StatisticsImpl : public Statistics {
+ public:
+  StatisticsImpl(std::shared_ptr<Statistics> stats);
+  virtual ~StatisticsImpl();
+  const char* Name() const override { return kClassName(); }
+  static const char* kClassName() { return "BasicStatistics"; }
+
+  virtual uint64_t getTickerCount(uint32_t ticker_type) const override;
+  virtual void histogramData(uint32_t histogram_type,
+                             HistogramData* const data) const override;
+  std::string getHistogramString(uint32_t histogram_type) const override;
+
+  virtual void setTickerCount(uint32_t ticker_type, uint64_t count) override;
+  virtual uint64_t getAndResetTickerCount(uint32_t ticker_type) override;
+  virtual void recordTick(uint32_t ticker_type, uint64_t count) override;
+  // The function is implemented for now for backward compatibility reason.
+  // In case a user explictly calls it, for example, they may have a wrapped
+  // Statistics object, passing the call to recordTick() into here, nothing
+  // will break.
+  void measureTime(uint32_t histogramType, uint64_t time) override {
+    recordInHistogram(histogramType, time);
+  }
+  virtual void recordInHistogram(uint32_t histogram_type,
+                                 uint64_t value) override;
+
+  virtual Status Reset() override;
+  virtual std::string ToString() const override;
+  virtual bool getTickerMap(std::map<std::string, uint64_t>*) const override;
+  virtual bool HistEnabledForType(uint32_t type) const override;
+
+  const Customizable* Inner() const override { return stats_.get(); }
+
+ private:
+  // If non-nullptr, forwards updates to the object pointed to by `stats_`.
+  std::shared_ptr<Statistics> stats_;
+  // Synchronizes anything that operates across other cores' local data,
+  // such that operations like Reset() can be performed atomically.
+  mutable port::Mutex aggregate_lock_;
+
+  // The ticker/histogram data are stored in this structure, which we will store
+  // per-core. It is cache-aligned, so tickers/histograms belonging to different
+  // cores can never share the same cache line.
+  //
+  // Alignment attributes expand to nothing depending on the platform
+  struct ALIGN_AS(CACHE_LINE_SIZE) StatisticsData {
+    std::atomic_uint_fast64_t tickers_[INTERNAL_TICKER_ENUM_MAX] = {{0}};
+    HistogramImpl histograms_[INTERNAL_HISTOGRAM_ENUM_MAX];
+#ifndef HAVE_ALIGNED_NEW
+    char
+        padding[(CACHE_LINE_SIZE -
+                 (INTERNAL_TICKER_ENUM_MAX * sizeof(std::atomic_uint_fast64_t) +
+                  INTERNAL_HISTOGRAM_ENUM_MAX * sizeof(HistogramImpl)) %
+                     CACHE_LINE_SIZE)] ROCKSDB_FIELD_UNUSED;
+#endif
+    void* operator new(size_t s) { return port::cacheline_aligned_alloc(s); }
+    void* operator new[](size_t s) { return port::cacheline_aligned_alloc(s); }
+    void operator delete(void* p) { port::cacheline_aligned_free(p); }
+    void operator delete[](void* p) { port::cacheline_aligned_free(p); }
+  };
+
+#ifndef TEST_CACHE_LINE_SIZE
+  static_assert(sizeof(StatisticsData) % CACHE_LINE_SIZE == 0,
+                "Expected " TOSTRING(CACHE_LINE_SIZE) "-byte aligned");
+#endif
+
+  CoreLocalArray<StatisticsData> per_core_stats_;
+
+  uint64_t getTickerCountLocked(uint32_t ticker_type) const;
+  std::unique_ptr<HistogramImpl> getHistogramImplLocked(
+      uint32_t histogram_type) const;
+  void setTickerCountLocked(uint32_t ticker_type, uint64_t count);
+};
+
+// Utility functions
+inline void RecordInHistogram(Statistics* statistics, uint32_t histogram_type,
+                              uint64_t value) {
+  if (statistics) {
+    statistics->recordInHistogram(histogram_type, value);
+  }
+}
+
+inline void RecordTimeToHistogram(Statistics* statistics,
+                                  uint32_t histogram_type, uint64_t value) {
+  if (statistics) {
+    statistics->reportTimeToHistogram(histogram_type, value);
+  }
+}
+
+inline void RecordTick(Statistics* statistics, uint32_t ticker_type,
+                       uint64_t count = 1) {
+  if (statistics) {
+    statistics->recordTick(ticker_type, count);
+  }
+}
+
+inline void SetTickerCount(Statistics* statistics, uint32_t ticker_type,
+                           uint64_t count) {
+  if (statistics) {
+    statistics->setTickerCount(ticker_type, count);
+  }
+}
+
+}  // namespace ROCKSDB_NAMESPACE