src/utils/PerformanceStatistics.ts

   1 // Partial Copyright Jerome Benoit. 2021. All Rights Reserved.
   2
   3 import { CircularArray, DEFAULT_CIRCULAR_ARRAY_SIZE } from './CircularArray';
   4 import { IncomingRequestCommand, RequestCommand } from '../types/ocpp/Requests';
   5 import { PerformanceEntry, PerformanceObserver, performance } from 'perf_hooks';
   6 import Statistics, { StatisticsData } from '../types/Statistics';
   7
   8 import Configuration from './Configuration';
   9 import { MessageType } from '../types/ocpp/MessageType';
  10 import Utils from './Utils';
  11 import logger from './Logger';
  12
  13 export default class PerformanceStatistics {
  14   private objId: string;
  15   private performanceObserver: PerformanceObserver;
  16   private statistics: Statistics;
  17   private displayInterval: NodeJS.Timeout;
  18
  19   public constructor(objId: string) {
  20     this.objId = objId;
  21     this.initializePerformanceObserver();
  22     this.statistics = { id: this.objId ?? 'Object id not specified', statisticsData: {} };
  23   }
  24
  25   public static beginMeasure(id: string): string {
  26     const beginId = 'begin' + id.charAt(0).toUpperCase() + id.slice(1);
  27     performance.mark(beginId);
  28     return beginId;
  29   }
  30
  31   public static endMeasure(name: string, beginId: string): void {
  32     performance.measure(name, beginId);
  33     performance.clearMarks(beginId);
  34   }
  35
  36   public addRequestStatistic(command: RequestCommand | IncomingRequestCommand, messageType: MessageType): void {
  37     switch (messageType) {
  38       case MessageType.CALL_MESSAGE:
  39         if (this.statistics.statisticsData[command] && this.statistics.statisticsData[command].countRequest) {
  40           this.statistics.statisticsData[command].countRequest++;
  41         } else {
  42           this.statistics.statisticsData[command] = {} as StatisticsData;
  43           this.statistics.statisticsData[command].countRequest = 1;
  44         }
  45         break;
  46       case MessageType.CALL_RESULT_MESSAGE:
  47         if (this.statistics.statisticsData[command]) {
  48           if (this.statistics.statisticsData[command].countResponse) {
  49             this.statistics.statisticsData[command].countResponse++;
  50           } else {
  51             this.statistics.statisticsData[command].countResponse = 1;
  52           }
  53         } else {
  54           this.statistics.statisticsData[command] = {} as StatisticsData;
  55           this.statistics.statisticsData[command].countResponse = 1;
  56         }
  57         break;
  58       case MessageType.CALL_ERROR_MESSAGE:
  59         if (this.statistics.statisticsData[command]) {
  60           if (this.statistics.statisticsData[command].countError) {
  61             this.statistics.statisticsData[command].countError++;
  62           } else {
  63             this.statistics.statisticsData[command].countError = 1;
  64           }
  65         } else {
  66           this.statistics.statisticsData[command] = {} as StatisticsData;
  67           this.statistics.statisticsData[command].countError = 1;
  68         }
  69         break;
  70       default:
  71         logger.error(`${this.logPrefix()} wrong message type ${messageType}`);
  72         break;
  73     }
  74   }
  75
  76   public start(): void {
  77     this.startDisplayInterval();
  78   }
  79
  80   public stop(): void {
  81     if (this.displayInterval) {
  82       clearInterval(this.displayInterval);
  83     }
  84     performance.clearMarks();
  85     this.performanceObserver?.disconnect();
  86   }
  87
  88   public restart(): void {
  89     this.stop();
  90     this.start();
  91   }
  92
  93   private initializePerformanceObserver(): void {
  94     this.performanceObserver = new PerformanceObserver((list) => {
  95       this.addPerformanceEntryToStatistics(list.getEntries()[0]);
  96       logger.debug(`${this.logPrefix()} '${list.getEntries()[0].name}' performance entry: %j`, list.getEntries()[0]);
  97     });
  98     this.performanceObserver.observe({ entryTypes: ['measure'] });
  99   }
 100
 101   private logStatistics(): void {
 102     logger.info(this.logPrefix() + ' %j', this.statistics);
 103   }
 104
 105   private startDisplayInterval(): void {
 106     if (Configuration.getStatisticsDisplayInterval() > 0) {
 107       this.displayInterval = setInterval(() => {
 108         this.logStatistics();
 109       }, Configuration.getStatisticsDisplayInterval() * 1000);
 110       logger.info(this.logPrefix() + ' displayed every ' + Utils.secondsToHHMMSS(Configuration.getStatisticsDisplayInterval()));
 111     } else {
 112       logger.info(this.logPrefix() + ' display interval is set to ' + Configuration.getStatisticsDisplayInterval().toString() + '. Not displaying statistics');
 113     }
 114   }
 115
 116   private median(dataSet: number[]): number {
 117     if (Array.isArray(dataSet) && dataSet.length === 1) {
 118       return dataSet[0];
 119     }
 120     const sortedDataSet = dataSet.slice().sort((a, b) => (a - b));
 121     const middleIndex = Math.floor(sortedDataSet.length / 2);
 122     if (sortedDataSet.length % 2) {
 123       return sortedDataSet[middleIndex / 2];
 124     }
 125     return (sortedDataSet[(middleIndex - 1)] + sortedDataSet[middleIndex]) / 2;
 126   }
 127
 128   // TODO: use order statistics tree https://en.wikipedia.org/wiki/Order_statistic_tree
 129   private percentile(dataSet: number[], percentile: number): number {
 130     if (percentile < 0 && percentile > 100) {
 131       throw new RangeError('Percentile is not between 0 and 100');
 132     }
 133     if (Utils.isEmptyArray(dataSet)) {
 134       return 0;
 135     }
 136     const sortedDataSet = dataSet.slice().sort((a, b) => (a - b));
 137     if (percentile === 0) {
 138       return sortedDataSet[0];
 139     }
 140     if (percentile === 100) {
 141       return sortedDataSet[sortedDataSet.length - 1];
 142     }
 143     const percentileIndex = ((percentile / 100) * sortedDataSet.length) - 1;
 144     if (Number.isInteger(percentileIndex)) {
 145       return (sortedDataSet[percentileIndex] + sortedDataSet[percentileIndex + 1]) / 2;
 146     }
 147     return sortedDataSet[Math.round(percentileIndex)];
 148   }
 149
 150   private stdDeviation(dataSet: number[]): number {
 151     let totalDataSet = 0;
 152     for (const data of dataSet) {
 153       totalDataSet += data;
 154     }
 155     const dataSetMean = totalDataSet / dataSet.length;
 156     let totalGeometricDeviation = 0;
 157     for (const data of dataSet) {
 158       const deviation = data - dataSetMean;
 159       totalGeometricDeviation += deviation * deviation;
 160     }
 161     return Math.sqrt(totalGeometricDeviation / dataSet.length);
 162   }
 163
 164   private addPerformanceEntryToStatistics(entry: PerformanceEntry): void {
 165     let entryName = entry.name;
 166     // Rename entry name
 167     const MAP_NAME: Record<string, string> = {};
 168     if (MAP_NAME[entryName]) {
 169       entryName = MAP_NAME[entryName];
 170     }
 171     // Initialize command statistics
 172     if (!this.statistics.statisticsData[entryName]) {
 173       this.statistics.statisticsData[entryName] = {} as StatisticsData;
 174     }
 175     // Update current statistics
 176     this.statistics.statisticsData[entryName].countTimeMeasurement = this.statistics.statisticsData[entryName].countTimeMeasurement ? this.statistics.statisticsData[entryName].countTimeMeasurement + 1 : 1;
 177     this.statistics.statisticsData[entryName].currentTimeMeasurement = entry.duration;
 178     this.statistics.statisticsData[entryName].minTimeMeasurement = this.statistics.statisticsData[entryName].minTimeMeasurement ? (this.statistics.statisticsData[entryName].minTimeMeasurement > entry.duration ? entry.duration : this.statistics.statisticsData[entryName].minTimeMeasurement) : entry.duration;
 179     this.statistics.statisticsData[entryName].maxTimeMeasurement = this.statistics.statisticsData[entryName].maxTimeMeasurement ? (this.statistics.statisticsData[entryName].maxTimeMeasurement < entry.duration ? entry.duration : this.statistics.statisticsData[entryName].maxTimeMeasurement) : entry.duration;
 180     this.statistics.statisticsData[entryName].totalTimeMeasurement = this.statistics.statisticsData[entryName].totalTimeMeasurement ? this.statistics.statisticsData[entryName].totalTimeMeasurement + entry.duration : entry.duration;
 181     this.statistics.statisticsData[entryName].avgTimeMeasurement = this.statistics.statisticsData[entryName].totalTimeMeasurement / this.statistics.statisticsData[entryName].countTimeMeasurement;
 182     Array.isArray(this.statistics.statisticsData[entryName].timeMeasurementSeries) ? this.statistics.statisticsData[entryName].timeMeasurementSeries.push(entry.duration) : this.statistics.statisticsData[entryName].timeMeasurementSeries = new CircularArray<number>(DEFAULT_CIRCULAR_ARRAY_SIZE, entry.duration);
 183     this.statistics.statisticsData[entryName].medTimeMeasurement = this.median(this.statistics.statisticsData[entryName].timeMeasurementSeries);
 184     this.statistics.statisticsData[entryName].ninetyFiveThPercentileTimeMeasurement = this.percentile(this.statistics.statisticsData[entryName].timeMeasurementSeries, 95);
 185     this.statistics.statisticsData[entryName].stdDevTimeMeasurement = this.stdDeviation(this.statistics.statisticsData[entryName].timeMeasurementSeries);
 186   }
 187
 188   private logPrefix(): string {
 189     return Utils.logPrefix(` ${this.objId} | Performance statistics`);
 190   }
 191 }