Statistics: Fix histogram.

Signed-off-by: Pascal Spörri <[email protected]>
IBM · Mar 25, 2023 · 4df04c0 · 4df04c0
1 parent 93eadfc
commit 4df04c0
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Showing 2 changed files with 13 additions and 25 deletions.
diff --git a/src/statistics/Statistics.cpp b/src/statistics/Statistics.cpp
@@ -72,20 +72,8 @@ std::shared_ptr<StatisticsHistogram>
 Statistics::createNanoSecondHistogram(const std::string &label) {
   constexpr size_t ONE_MIN = 60000000000; // Minute
   const static auto NANOSECOND_HISTOGRAM = std::vector<size_t>{
-      010,          020,          030,          040,          050,          // 50ns
-      100,          200,          300,          400,          500,          // 0.5us
-      1000,         2000,         3000,         4000,         5000,         // 5us
-      10000,        20000,        30000,        40000,        50000,        // 50us
-      100000,       200000,       300000,       400000,       500000,       // 500us
-      1000000,      2000000,      3000000,      4000000,      5000000,      // 5ms
-      10000000,     20000000,     30000000,     40000000,     50000000,     // 50ms
-      100000000,    200000000,    300000000,    400000000,    500000000,    // 500ms
-      1000000000,   2000000000,   3000000000,   4000000000,   5000000000,   // 5s
-      10000000000,  20000000000,  30000000000,  40000000000,  50000000000,  // 50s
-      ONE_MIN * 1,  ONE_MIN * 2,  ONE_MIN * 3,  ONE_MIN * 4,  ONE_MIN * 5,  // 5min,
-      ONE_MIN * 10, ONE_MIN * 20, ONE_MIN * 30, ONE_MIN * 40, ONE_MIN * 50, // 50min
-      ONE_MIN * 60                                                          // 1h
-  };
+      1,        10,        100,        1000,        10000,       100000,       1000000,
+      10000000, 100000000, 1000000000, 10000000000, ONE_MIN * 1, ONE_MIN * 10, ONE_MIN * 60};
 
   return createHistogram(label, NANOSECOND_HISTOGRAM);
 }

diff --git a/src/statistics/StatisticsHistogram.h b/src/statistics/StatisticsHistogram.h
@@ -18,11 +18,11 @@ namespace geds {
 
 class StatisticsHistogram : public StatisticsItem {
   std::atomic<size_t> _sum;
-  std::atomic<size_t> _total;
+  std::atomic<size_t> _totalCount;
   std::vector<std::atomic<size_t>> _count;
   const std::vector<size_t> &_buckets;
   StatisticsHistogram(std::string labelArg, const std::vector<size_t> &buckets)
-      : StatisticsItem(std::move(labelArg)), _count(buckets.size() + 1), _buckets(buckets) {
+      : StatisticsItem(std::move(labelArg)), _count(buckets.size()), _buckets(buckets) {
     for (auto &c : _count) {
       c = (size_t)0;
     }
@@ -35,29 +35,29 @@ class StatisticsHistogram : public StatisticsItem {
     for (size_t i = 0; i < _buckets.size(); i++) {
       stream << prometheusLabel << "_bucket{le=\"" << _buckets[i] << "\"} " << _count[i] << "\n";
     }
-    stream << prometheusLabel << "_bucket{le=\"+Inf\"}" << _count[_buckets.size()] << "\n"
+    stream << prometheusLabel << "_bucket{le=\"+Inf\"} " << _totalCount << "\n"
            << prometheusLabel << "_sum " << _sum << "\n"
-           << prometheusLabel << "_count " << _total << std::endl;
+           << prometheusLabel << "_count " << _totalCount << std::endl;
   }
 
   void printForConsole(std::stringstream &stream) const override {
-    stream << label << ", " << _total << ", sum " << _sum << ", ";
+    stream << label << ", " << _totalCount << ", sum " << _sum << ", ";
     for (size_t i = 0; i < _buckets.size(); i++) {
       stream << " {le=" << _buckets[i] << "} " << _count[i] << ", ";
     }
-    stream << " {le=+Inf }" << _count[_buckets.size()] << std::endl;
+    stream << " {le=+Inf} " << _totalCount << std::endl;
   }
 
-  StatisticsItem &operator+=(size_t value) override {
+  StatisticsHistogram &operator+=(size_t value) override {
+    // https://prometheus.io/docs/concepts/metric_types/#histogram
     _sum += value;
-    _total += 1;
+    _totalCount += 1; // Corresponds to <basename>_bucket{le="+Inf"}
     for (size_t i = 0; i < _buckets.size(); i++) {
-      if (value < _buckets[i]) {
-        return *this;
+      if (value > _buckets[i]) {
+        continue;
       }
       _count[i] += 1;
     }
-    _count[_buckets.size()] += 1;
     return *this;
   }