ceph/src/rocksdb/monitoring/statistics.h

   1 //  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 //  This source code is licensed under both the GPLv2 (found in the
   3 //  COPYING file in the root directory) and Apache 2.0 License
   4 //  (found in the LICENSE.Apache file in the root directory).
   5 //
   6 #pragma once
   7 #include "rocksdb/statistics.h"
   8
   9 #include <vector>
  10 #include <atomic>
  11 #include <string>
  12
  13 #include "monitoring/histogram.h"
  14 #include "port/likely.h"
  15 #include "port/port.h"
  16 #include "util/core_local.h"
  17 #include "util/mutexlock.h"
  18
  19 #ifdef __clang__
  20 #define ROCKSDB_FIELD_UNUSED __attribute__((__unused__))
  21 #else
  22 #define ROCKSDB_FIELD_UNUSED
  23 #endif  // __clang__
  24
  25 #ifndef STRINGIFY
  26 #define STRINGIFY(x) #x
  27 #define TOSTRING(x) STRINGIFY(x)
  28 #endif
  29
  30 namespace rocksdb {
  31
  32 enum TickersInternal : uint32_t {
  33   INTERNAL_TICKER_ENUM_START = TICKER_ENUM_MAX,
  34   INTERNAL_TICKER_ENUM_MAX
  35 };
  36
  37 enum HistogramsInternal : uint32_t {
  38   INTERNAL_HISTOGRAM_START = HISTOGRAM_ENUM_MAX,
  39   INTERNAL_HISTOGRAM_ENUM_MAX
  40 };
  41
  42 class StatisticsImpl : public Statistics {
  43  public:
  44   StatisticsImpl(std::shared_ptr<Statistics> stats,
  45                  bool enable_internal_stats);
  46   virtual ~StatisticsImpl();
  47
  48   virtual uint64_t getTickerCount(uint32_t ticker_type) const override;
  49   virtual void histogramData(uint32_t histogram_type,
  50                              HistogramData* const data) const override;
  51   std::string getHistogramString(uint32_t histogram_type) const override;
  52
  53   virtual void setTickerCount(uint32_t ticker_type, uint64_t count) override;
  54   virtual uint64_t getAndResetTickerCount(uint32_t ticker_type) override;
  55   virtual void recordTick(uint32_t ticker_type, uint64_t count) override;
  56   virtual void measureTime(uint32_t histogram_type, uint64_t value) override;
  57
  58   virtual Status Reset() override;
  59   virtual std::string ToString() const override;
  60   virtual bool HistEnabledForType(uint32_t type) const override;
  61
  62  private:
  63   // If non-nullptr, forwards updates to the object pointed to by `stats_`.
  64   std::shared_ptr<Statistics> stats_;
  65   // TODO(ajkr): clean this up since there are no internal stats anymore
  66   bool enable_internal_stats_;
  67   // Synchronizes anything that operates across other cores' local data,
  68   // such that operations like Reset() can be performed atomically.
  69   mutable port::Mutex aggregate_lock_;
  70
  71   // The ticker/histogram data are stored in this structure, which we will store
  72   // per-core. It is cache-aligned, so tickers/histograms belonging to different
  73   // cores can never share the same cache line.
  74   //
  75   // Alignment attributes expand to nothing depending on the platform
  76   struct ALIGN_AS(CACHE_LINE_SIZE) StatisticsData {
  77     std::atomic_uint_fast64_t tickers_[INTERNAL_TICKER_ENUM_MAX] = {{0}};
  78     HistogramImpl histograms_[INTERNAL_HISTOGRAM_ENUM_MAX];
  79 #ifndef HAVE_ALIGNED_NEW
  80     char
  81         padding[(CACHE_LINE_SIZE -
  82                  (INTERNAL_TICKER_ENUM_MAX * sizeof(std::atomic_uint_fast64_t) +
  83                   INTERNAL_HISTOGRAM_ENUM_MAX * sizeof(HistogramImpl)) %
  84                      CACHE_LINE_SIZE)] ROCKSDB_FIELD_UNUSED;
  85 #endif
  86     void *operator new(size_t s) { return port::cacheline_aligned_alloc(s); }
  87     void *operator new[](size_t s) { return port::cacheline_aligned_alloc(s); }
  88     void operator delete(void *p) { port::cacheline_aligned_free(p); }
  89     void operator delete[](void *p) { port::cacheline_aligned_free(p); }
  90   };
  91
  92   static_assert(sizeof(StatisticsData) % CACHE_LINE_SIZE == 0, "Expected " TOSTRING(CACHE_LINE_SIZE) "-byte aligned");
  93
  94   CoreLocalArray<StatisticsData> per_core_stats_;
  95
  96   uint64_t getTickerCountLocked(uint32_t ticker_type) const;
  97   std::unique_ptr<HistogramImpl> getHistogramImplLocked(
  98       uint32_t histogram_type) const;
  99   void setTickerCountLocked(uint32_t ticker_type, uint64_t count);
 100 };
 101
 102 // Utility functions
 103 inline void MeasureTime(Statistics* statistics, uint32_t histogram_type,
 104                         uint64_t value) {
 105   if (statistics) {
 106     statistics->measureTime(histogram_type, value);
 107   }
 108 }
 109
 110 inline void RecordTick(Statistics* statistics, uint32_t ticker_type,
 111                        uint64_t count = 1) {
 112   if (statistics) {
 113     statistics->recordTick(ticker_type, count);
 114   }
 115 }
 116
 117 inline void SetTickerCount(Statistics* statistics, uint32_t ticker_type,
 118                            uint64_t count) {
 119   if (statistics) {
 120     statistics->setTickerCount(ticker_type, count);
 121   }
 122 }
 123
 124 }