1 /*
2  * Copyright (c) 2001 by Matt Welsh and The Regents of the University of
3  * California. All rights reserved.
4  *
5  * Permission to use, copy, modify, and distribute this software and its
6  * documentation for any purpose, without fee, and without written agreement is
7  * hereby granted, provided that the above copyright notice and the following
8  * two paragraphs appear in all copies of this software.
9  *
10  * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
11  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
12  * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
13  * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
14  *
15  * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
16  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
17  * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
18  * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
19  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
20  *
21  * Author: Matt Welsh <mdw@cs.berkeley.edu>
22  *
23  */
24 
25 package seda.sandStorm.internal;
26 
27 import seda.sandStorm.api.*;
28 import seda.sandStorm.api.internal.*;
29 import seda.sandStorm.core.*;
30 import seda.sandStorm.main.*;
31 import java.util.*;
32 
33 /**
34  * This class provides controllers with a view of statistics gathered
35  * by the stage internally during execution.
36  *
37  * @author   Matt Welsh
38  */
39 
40 public class StageStats implements StageStatsIF {
41   private static final boolean DEBUG = false;
42   private static final boolean PROFILE = false;
43 
44   private static final double SMOOTH_ALPHA = 0.7;
45   private static final int ESTIMATION_SIZE = 100;
46   private static final long ESTIMATION_TIME = 1000;
47 
48   /* A handle to the stage. */
49   StageWrapperIF stage;
50 
51   /* Average service rate of events. */
52   private double serviceRate;
53 
54   /* 90th percentile response time of the stage. */
55   private double rt90thPercentile;
56 
57   private boolean first = true;
58   private long lastTime;
59   private int count;
60   private long totalServiceTime, totalEvents, cumulativeEvents;
61 
StageStats(StageWrapperIF stage)62   public StageStats(StageWrapperIF stage) {
63     this.stage = stage;
64     reset();
65   }
66 
67   /** Reset all statistics. */
reset()68   public void reset() {
69     serviceRate = 0.0;
70     count = 0;
71     lastTime = System.currentTimeMillis();
72     totalEvents = totalServiceTime = cumulativeEvents = 0;
73   }
74 
75   /** Return a moving average of the service rate. */
getServiceRate()76   public synchronized double getServiceRate() {
77     return serviceRate;
78   }
79 
80   /** Get total number of processed events. */
getTotalEvents()81   public synchronized long getTotalEvents() {
82     return this.cumulativeEvents;
83   }
84 
85   /**
86    * Record the service time for numEvents taking 'time' msec to
87    * be processed.
88    */
recordServiceRate(int numEvents, long time)89   public synchronized void recordServiceRate(int numEvents, long time) {
90 
91     // Only possible to add ourselves to the profile after we start running
92     if (PROFILE && first) {
93       first = false;
94       ManagerIF mgr = Sandstorm.getSandstorm().getManager();
95       if (mgr.getProfiler() != null) {
96 	mgr.getProfiler().add("StageStats serviceRate <"+stage.getStage().getName()+">",
97 	    new ProfilableIF() {
98 	    public int profileSize() {
99 	    return (int)serviceRate;
100 	    }});
101       }
102     }
103 
104     totalEvents += numEvents;
105     cumulativeEvents += numEvents;
106     totalServiceTime += time;
107 
108     count++;
109     long curTime = System.currentTimeMillis();
110 
111     if ((count == ESTIMATION_SIZE) ||
112 	(curTime - lastTime >= ESTIMATION_TIME)) {
113       if (totalServiceTime == 0) totalServiceTime = 1;
114       double rate = totalEvents / (totalServiceTime * 1.0e-3);
115       serviceRate = (rate * SMOOTH_ALPHA) + (serviceRate * (1.0 - SMOOTH_ALPHA));
116       if (DEBUG) System.err.println("Stats <"+stage.getStage().getName()+">: numEvents="+totalEvents+" time="+totalServiceTime+", rate="+serviceRate);
117       count = 0;
118       lastTime = curTime;
119       totalEvents = totalServiceTime = 0;
120     }
121   }
122 
123   /** Record 90th percentile response time in msec. */
record90thRT(double rt_sample)124   public synchronized void record90thRT(double rt_sample) {
125     this.rt90thPercentile = rt_sample;
126   }
127 
128   /** Get 90th percentile response time in msec. */
get90thRT()129   public synchronized double get90thRT() {
130     return this.rt90thPercentile;
131   }
132 
133 
134 
135 }
136 
137