livestatus/src/global_counters.cc

   1 // +------------------------------------------------------------------+
   2 // |             ____ _               _        __  __ _  __           |
   3 // |            / ___| |__   ___  ___| | __   |  \/  | |/ /           |
   4 // |           | |   | '_ \ / _ \/ __| |/ /   | |\/| | ' /            |
   5 // |           | |___| | | |  __/ (__|   <    | |  | | . \            |
   6 // |            \____|_| |_|\___|\___|_|\_\___|_|  |_|_|\_\           |
   7 // |                                                                  |
   8 // | Copyright Mathias Kettner 2014             mk@mathias-kettner.de |
   9 // +------------------------------------------------------------------+
  10 //
  11 // This file is part of Check_MK.
  12 // The official homepage is at http://mathias-kettner.de/check_mk.
  13 //
  14 // check_mk is free software;  you can redistribute it and/or modify it
  15 // under the  terms of the  GNU General Public License  as published by
  16 // the Free Software Foundation in version 2.  check_mk is  distributed
  17 // in the hope that it will be useful, but WITHOUT ANY WARRANTY;  with-
  18 // out even the implied warranty of  MERCHANTABILITY  or  FITNESS FOR A
  19 // PARTICULAR PURPOSE. See the  GNU General Public License for more de-
  20 // tails. You should have  received  a copy of the  GNU  General Public
  21 // License along with GNU Make; see the file  COPYING.  If  not,  write
  22 // to the Free Software Foundation, Inc., 51 Franklin St,  Fifth Floor,
  23 // Boston, MA 02110-1301 USA.
  24
  25 #include "global_counters.h"
  26 #include <ctime>
  27 #include <vector>
  28
  29 namespace {
  30 constexpr int num_counters = 11;
  31
  32 struct CounterInfo {
  33     double value;
  34     double last_value;
  35     double rate;
  36 };
  37
  38 std::vector<CounterInfo> counters(num_counters);
  39
  40 CounterInfo &counter(Counter which) {
  41     return counters[static_cast<int>(which)];
  42 }
  43
  44 time_t last_statistics_update = 0;
  45 constexpr time_t statistics_interval = 5;
  46 constexpr double rating_weight = 0.25;
  47
  48 double lerp(double a, double b, double t) { return (1 - t) * a + t * b; }
  49 }  // namespace
  50
  51 void counterIncrement(Counter which) { counter(which).value++; }
  52
  53 const double *counterAddress(Counter which) { return &counter(which).value; }
  54
  55 const double *counterRateAddress(Counter which) { return &counter(which).rate; }
  56
  57 void do_statistics() {
  58     time_t now = time(nullptr);
  59     if (last_statistics_update == 0) {
  60         last_statistics_update = now;
  61         return;
  62     }
  63     time_t delta_time = now - last_statistics_update;
  64     if (delta_time < statistics_interval) {
  65         return;
  66     }
  67     last_statistics_update = now;
  68     for (auto &c : counters) {
  69         double old_rate = c.rate;
  70         double new_rate = (c.value - c.last_value) / delta_time;
  71         c.rate = lerp(old_rate, new_rate, old_rate == 0 ? 1 : rating_weight);
  72         c.last_value = c.value;
  73     }
  74 }