legacy-libs/grpc-cloned/deps/grpc/src/core/lib/iomgr/time_averaged_stats.cc

   1 /*
   2  *
   3  * Copyright 2015 gRPC authors.
   4  *
   5  * Licensed under the Apache License, Version 2.0 (the "License");
   6  * you may not use this file except in compliance with the License.
   7  * You may obtain a copy of the License at
   8  *
   9  *     http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  *
  17  */
  18
  19 #include <grpc/support/port_platform.h>
  20
  21 #include "src/core/lib/iomgr/time_averaged_stats.h"
  22
  23 void grpc_time_averaged_stats_init(grpc_time_averaged_stats* stats,
  24                                    double init_avg, double regress_weight,
  25                                    double persistence_factor) {
  26   stats->init_avg = init_avg;
  27   stats->regress_weight = regress_weight;
  28   stats->persistence_factor = persistence_factor;
  29   stats->batch_total_value = 0;
  30   stats->batch_num_samples = 0;
  31   stats->aggregate_total_weight = 0;
  32   stats->aggregate_weighted_avg = init_avg;
  33 }
  34
  35 void grpc_time_averaged_stats_add_sample(grpc_time_averaged_stats* stats,
  36                                          double value) {
  37   stats->batch_total_value += value;
  38   ++stats->batch_num_samples;
  39 }
  40
  41 double grpc_time_averaged_stats_update_average(
  42     grpc_time_averaged_stats* stats) {
  43   /* Start with the current batch: */
  44   double weighted_sum = stats->batch_total_value;
  45   double total_weight = stats->batch_num_samples;
  46   if (stats->regress_weight > 0) {
  47     /* Add in the regression towards init_avg_: */
  48     weighted_sum += stats->regress_weight * stats->init_avg;
  49     total_weight += stats->regress_weight;
  50   }
  51   if (stats->persistence_factor > 0) {
  52     /* Add in the persistence: */
  53     const double prev_sample_weight =
  54         stats->persistence_factor * stats->aggregate_total_weight;
  55     weighted_sum += prev_sample_weight * stats->aggregate_weighted_avg;
  56     total_weight += prev_sample_weight;
  57   }
  58   stats->aggregate_weighted_avg =
  59       (total_weight > 0) ? (weighted_sum / total_weight) : stats->init_avg;
  60   stats->aggregate_total_weight = total_weight;
  61   stats->batch_num_samples = 0;
  62   stats->batch_total_value = 0;
  63   return stats->aggregate_weighted_avg;
  64 }