PERF


1   // $Id: PERF.java,v 1.8 2005/04/20 06:31:17 belaban Exp $
2   
3   package org.jgroups.protocols;
4   
5   import org.jgroups.Event;
6   import org.jgroups.Message;
7   import org.jgroups.View;
8   import org.jgroups.stack.Protocol;
9   import org.jgroups.stack.ProtocolObserver;
10  
11  import java.util.Properties  ;
12  import java.util.Vector  ;
13  
14  
15  /**
16   * Measures time taken by each protocol to process a message. PERF has to be the top protocol in a stack. It
17   * adds a special header to the message which travels with the message. Upon initialization,
18   * PERF creates a ProtocolObserver for each protocol layer in the stack. That observer notes the time taken for a
19   * message to travel through the layer it observes, and records the start time, end time and total time
20   * <em>in the message itself</em> (in the header created by PERF). When a message is received by PERF, the statistics
21   * for the message are appended to a file (or displayed in a GUI (not yet done)).<p>
22   * <em>Because of different wall times between different machines, PERF should only be used for members
23   * in the same JVM. For members in different processes, physical clocks have to be synchronized: if they are
24   * only a few milliseconds aprt, the values will be incorrect.</em>
25   * For example, to write all performance data to a file, do the following:
26   * <ol>
27   * <li>Set tracing to on, e.g. <code>trace=true</code> in jgroups.properties
28   * <li>Add a trace statement for PERF.up(): <code>trace0=PERF.up DEBUG /tmp/trace.perf</code>. This will write
29   * all trace output to the given file.
30   * </ol>
31   *
32   * @author Bela Ban Oct 2001
33   * @version $Revision: 1.8 $
34   */
35  public class PERF extends Protocol {
36      boolean             details=false;
37      final Vector          members=new Vector  ();
38      Vector                protocols=null;
39      static final String   name="PERF";
40  
41  
42      /**
43       * All protocol names have to be unique !
44       */
45      public String   getName() {
46          return name;
47      }
48  
49  
50      public boolean setProperties(Properties   props) {
51          super.setProperties(props);
52          String   str;
53  
54          str=props.getProperty("details");
55          if(str != null) {
56              details=Boolean.valueOf(str).booleanValue();
57              props.remove("details");
58          }
59          if(props.size() > 0) {
60              System.err.println("PERF.setProperties(): these properties are not recognized:");
61              props.list(System.out);
62              return false;
63          }
64          return true;
65      }
66  
67  
68      public void start() throws Exception   {
69          protocols=stack != null ? stack.getProtocols() : null;
70          setupObservers();
71      }
72  
73  
74      public void up(Event evt) {
75          Message msg;
76          PerfHeader hdr;
77  
78          switch(evt.getType()) {
79  
80          case Event.MSG:
81              msg=(Message)evt.getArg();
82              hdr=removePerfHeader(msg);
83              if(hdr != null) {
84                  hdr.setEndTime();
85                  hdr.setDone(name, PerfHeader.UP); // we do this here because header is removed, so PassUp won't find it
86                  if(log.isTraceEnabled())
87                      log.trace(hdr.printContents(details, protocols) + "\n---------------------------------\n");
88              }
89              break;
90          }
91  
92          passUp(evt);            // Pass up to the layer above us
93      }
94  
95  
96      public void down(Event evt) {
97          Message msg;
98  
99          switch(evt.getType()) {
100 
101         case Event.TMP_VIEW:
102         case Event.VIEW_CHANGE:
103             Vector   new_members=((View)evt.getArg()).getMembers();
104             synchronized(members) {
105                 members.removeAllElements();
106                 members.addAll(new_members);
107             }
108             passDown(evt);
109             break;
110 
111         case Event.MSG:
112             msg=(Message)evt.getArg();
113             initializeMessage(msg); // Add a PerfHeader to the message
114             break;
115         }
116 
117         passDown(evt);          // Pass on to the layer below us
118     }
119 
120 
121     /* ----------------------------------- Private Methods -------------------------------------- */
122 
123     /**
124      * Create PerfObservers for all protocols save PERF
125      */
126     void setupObservers() {
127         Protocol p=null;
128         String   pname;
129         PerfObserver po=null;
130 
131         for(int i=0; i < protocols.size(); i++) {
132             p=(Protocol)protocols.elementAt(i);
133             pname=p.getName();
134             if(pname != null) {
135                 po=new PerfObserver(pname);
136                 p.setObserver(po);
137             }
138         }
139     }
140 
141 
142     void initializeMessage(Message msg) {
143         PerfHeader hdr=new PerfHeader(msg.getSrc(), msg.getDest());
144         Protocol p;
145         String   pname=null;
146 
147         if(protocols == null) {
148             System.err.println("PERF.initializeMessage(): 'protocols' variable is null");
149             return;
150         }
151 
152         for(int i=0; i < protocols.size(); i++) {
153             p=(Protocol)protocols.elementAt(i);
154             pname=p.getName();
155             if(pname != null) {
156                 hdr.addEntry(pname);
157             }
158         }
159         hdr.setReceived(name, PerfHeader.DOWN); // we do this here because down() didn't yet find a PerfHeader
160         msg.putHeader(name, hdr);
161     }
162 
163 
164     /**
165      * Removes if present. Otherwise returns null
166      */
167     PerfHeader removePerfHeader(Message m) {
168         Object   hdr=null;
169 
170         if(m == null || (hdr=m.removeHeader(name)) == null)
171             return null;
172         return (PerfHeader)hdr;
173     }
174 
175 
176 //      Vector getProtocols() {
177 //      Vector   ret=(Vector)stack.getProtocols().clone();
178 //      Protocol p;
179     
180 //      for(int i=0; i < ret.size(); i++) {
181 //          p=(Protocol)ret.elementAt(i);
182 //          if(p.getName() != null && p.getName().equals(getName())) {
183 //          ret.removeElement(p);
184 //          break;
185 //          }
186 //      }
187 //      return ret;
188 //      }
189 
190     /* -------------------------------- End of Private Methods ---------------------------------- */
191 }
192 
193 
194 /**
195  * Observes a protocol and adds its timings to the PerfHeader attached to each protocol.
196  */
197 class PerfObserver implements ProtocolObserver {
198     final String   prot_name;
199     boolean bottom=false;
200 
201     PerfObserver(String   prot_name) {
202         this.prot_name=prot_name;
203     }
204 
205 
206     public void setProtocol(Protocol prot) {
207         if(prot != null && prot.getDownProtocol() == null)
208             bottom=true;
209     }
210 
211 
212     public boolean up(Event evt, int num_evts) {
213         PerfHeader hdr;
214         if(evt.getType() == Event.MSG) {
215             hdr=getPerfHeader((Message)evt.getArg());
216             if(hdr != null) {
217                 hdr.setReceived(prot_name, PerfHeader.UP);
218                 if(bottom)
219                     hdr.setNetworkReceived();
220             }
221         }
222         return true;
223     }
224 
225 
226     public boolean passUp(Event evt) {
227         PerfHeader hdr;
228         if(evt.getType() == Event.MSG) {
229             hdr=getPerfHeader((Message)evt.getArg());
230             if(hdr != null) {
231                 hdr.setDone(prot_name, PerfHeader.UP);
232             }
233         }
234         return true;
235     }
236 
237 
238     public boolean down(Event evt, int num_evts) {
239         PerfHeader hdr;
240         if(evt.getType() == Event.MSG) {
241             hdr=getPerfHeader((Message)evt.getArg());
242             if(hdr != null) {
243                 hdr.setReceived(prot_name, PerfHeader.DOWN);
244             }
245         }
246         return true;
247     }
248 
249 
250     public boolean passDown(Event evt) {
251         PerfHeader hdr;
252         if(evt.getType() == Event.MSG) {
253             hdr=getPerfHeader((Message)evt.getArg());
254             if(hdr != null) {
255                 hdr.setDone(prot_name, PerfHeader.DOWN);
256                 if(bottom)
257                     hdr.setNetworkSent();
258             }
259         }
260         return true;
261     }
262 
263 
264     PerfHeader getPerfHeader(Message m) {
265         Object   hdr=null;
266 
267         if(m == null || (hdr=m.getHeader(PERF.name)) == null)
268             return null;
269         return (PerfHeader)hdr;
270     }
271 
272 
273 }
274
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