BasePerfTest


1   /*
2    Copyright (C) 2002-2004 MySQL AB
3   
4    This program is free software; you can redistribute it and/or modify
5    it under the terms of version 2 of the GNU General Public License as 
6    published by the Free Software Foundation.
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9    as it is applied to this software. View the full text of the 
10   exception in file EXCEPTIONS-CONNECTOR-J in the directory of this 
11   software distribution.
12  
13   This program is distributed in the hope that it will be useful,
14   but WITHOUT ANY WARRANTY; without even the implied warranty of
15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16   GNU General Public License for more details.
17  
18   You should have received a copy of the GNU General Public License
19   along with this program; if not, write to the Free Software
20   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
21  
22  
23  
24   */
25  package testsuite.perf;
26  
27  import testsuite.BaseTestCase;
28  
29  import java.text.NumberFormat  ;
30  
31  import java.util.ArrayList  ;
32  import java.util.List  ;
33  
34  /**
35   * Base class for performance test cases. Handles statistics.
36   * 
37   * @author Mark Matthews
38   */
39  public abstract class BasePerfTest extends BaseTestCase {
40      // ~ Static fields/initializers
41      // ---------------------------------------------
42  
43      /**
44       * Confidence interval lookup table, indexed by degrees of freedom at 95%.
45       */
46      private static final double[] T95 = { 12.706, 4.303, 3.182, 2.776, 2.571,
47              2.447, 2.365, 2.306, 2.262, 2.228, 2.201, 2.179, 2.160, 2.145,
48              2.131, 2.120, 2.110, 2.101, 2.093, 2.086, 2.080, 2.074, 2.069,
49              2.064, 2.060, 2.056, 2.052, 2.048, 2.045, 2.042 };
50  
51      /**
52       * Confidence interval lookup table, indexed by degrees of freedom at 99%.
53       */
54      private static final double[] T99 = { 63.657, 9.925, 5.841, 4.604, 4.032,
55              3.707, 3.499, 3.355, 3.250, 3.169, 3.106, 3.055, 3.012, 2.977,
56              2.947, 2.921, 2.898, 2.878, 2.861, 2.845, 2.831, 2.819, 2.807,
57              2.797, 2.787, 2.779, 2.771, 2.763, 2.756, 2.750 };
58  
59      static NumberFormat   numberFormatter = NumberFormat.getInstance();
60  
61      static {
62          numberFormatter.setMaximumFractionDigits(4);
63          numberFormatter.setMinimumFractionDigits(4);
64      }
65  
66      // ~ Instance fields
67      // --------------------------------------------------------
68  
69      /**
70       * List of values for each iteration
71       */
72      private List   testValuesList = new ArrayList  ();
73  
74      private double confidenceLevel = 95; // 95% by default
75  
76      private double confidenceValue = 0;
77  
78      private double intervalWidth = 0.1;
79  
80      private double meanValue = 0;
81  
82      private double squareSumValue = 0;
83  
84      private double sumValue = 0;
85  
86      private double variationValue = 0;
87  
88      /**
89       * The number of iterations that we have performed
90       */
91      private int numIterations = 0;
92  
93      // ~ Constructors
94      // -----------------------------------------------------------
95  
96      /**
97       * Creates a new BasePerfTest object.
98       * 
99       * @param name
100      *            the testcase name to perform.
101      */
102     public BasePerfTest(String   name) {
103         super(name);
104     }
105 
106     // ~ Methods
107     // ----------------------------------------------------------------
108 
109     /**
110      * Returns the meanValue.
111      * 
112      * @return double
113      */
114     public double getMeanValue() {
115         return this.meanValue;
116     }
117 
118     /**
119      * Sub-classes should override this to perform the operation to be measured.
120      * 
121      * @throws Exception
122      *             if an error occurs.
123      */
124     protected abstract void doOneIteration() throws Exception  ;
125 
126     /**
127      * Returns the current confidence level.
128      * 
129      * @return the current confindence level.
130      */
131     protected double getCurrentConfidence() {
132         return (this.intervalWidth - this.confidenceValue) * 100;
133     }
134 
135     /**
136      * Returns the current margin of error.
137      * 
138      * @return the current margin of error.
139      */
140     protected double getMarginOfError() {
141         return getConfidenceLookup()
142                 * (getStandardDeviationP() / Math.sqrt(this.numIterations));
143     }
144 
145     /**
146      * Returns the current STDDEV.
147      * 
148      * @return the current STDDEV
149      */
150     protected double getStandardDeviationP() {
151         if (this.numIterations < 1) {
152             return 0;
153         }
154 
155         return Math
156                 .sqrt(((this.numIterations * this.squareSumValue) - (this.sumValue * this.sumValue))
157                         / (this.numIterations * this.numIterations));
158     }
159 
160     /**
161      * Adds one test result to the statistics.
162      * 
163      * @param value
164      *            a single result representing the value being measured in the
165      *            test.
166      */
167     protected void addResult(double value) {
168         this.numIterations++;
169         this.testValuesList.add(new Double  (value));
170 
171         this.sumValue += value;
172         this.squareSumValue += (value * value);
173         this.meanValue = this.sumValue / this.numIterations;
174         this.variationValue = (this.squareSumValue / this.numIterations)
175                 - (this.meanValue * this.meanValue);
176 
177         // Can only have confidence when more than one test
178         // has been completed
179         if (this.numIterations > 1) {
180             this.confidenceValue = this.intervalWidth
181                     - ((2.0 * getConfidenceLookup() * Math
182                             .sqrt(this.variationValue
183                                     / (this.numIterations - 1.0))) / this.meanValue);
184         }
185     }
186 
187     /**
188      * Calls doIteration() the <code>numIterations</code> times, displaying
189      * the mean, std, margin of error and confidence level.
190      * 
191      * @param numIterations
192      *            the number of iterations to perform ( < 30)
193      * @throws Exception
194      *             if an error occurs.
195      */
196     protected void doIterations(int numIterations) throws Exception   {
197         for (int i = 0; i < numIterations; i++) {
198             doOneIteration();
199         }
200     }
201 
202     /**
203      * Reports the current results to STDOUT, preceeded by
204      * <code>additionalMessage</code> if not null.
205      * 
206      * @param additionalMessage
207      *            the additional message to print, or null if no message.
208      */
209     protected synchronized void reportResults(String   additionalMessage) {
210         StringBuffer   messageBuf = new StringBuffer  ();
211 
212         if (additionalMessage != null) {
213             messageBuf.append(additionalMessage);
214             messageBuf.append(": ");
215         }
216 
217         messageBuf.append(" mean: ");
218         messageBuf.append(numberFormatter.format(this.meanValue));
219         messageBuf.append(" stdevp: ");
220         messageBuf.append(numberFormatter.format(getStandardDeviationP()));
221         messageBuf.append(" m-o-e: ");
222         messageBuf.append(numberFormatter.format(getMarginOfError()));
223 
224         System.out.println(messageBuf.toString());
225     }
226 
227     private double getConfidenceLookup() {
228         if (this.confidenceLevel == 95) {
229             return T95[this.numIterations - 1];
230         } else if (this.confidenceLevel == 99) {
231             return T99[this.numIterations - 1];
232         } else {
233             throw new IllegalArgumentException  (
234                     "Confidence level must be 95 or 99");
235         }
236     }
237 }
238
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