DO NOT REPLY [Bug 29980] New: - xslt multithreaded performance

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http://issues.apache.org/bugzilla/show_bug.cgi?id=29980

xslt multithreaded performance

           Summary: xslt multithreaded performance
           Product: XalanJ2
           Version: 2.6
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: Normal
          Priority: Other
         Component: org.apache.xalan.transformer
        AssignedTo: xalan-dev@xml.apache.org
        ReportedBy: swalkaus@yahoo.com


A program that uses a single stylesheet and multiple threads to transform 
documents uses significantly more (roughly 60%) cpu time when the transform is 
not synchronized. This results in confusing performance characteristics for 
threaded applications (on a 2 cpu box, my application had a slight performance 
degradation when I increased from 1 thread to 2 and performance degraded 
significantly when the number of threads was greater than the number of cpus).

The inlined TransformerThread class can be used to demonstrate this behavior. I 
ran java version "1.4.2_04" with the options '-server' and "-
Djavax.xml.transform.TransformerFactory=org.apache.xalan.xsltc.trax.TransformerF
actoryImpl". The TransformerThread program takes a stylesheet file as its first 
argument (I've inlined xform.xsl which I used) and 'true'|'false' as its second 
argument to specify whether or not to synchronize the transform code block.

TransformerThread class:
import java.io.*;
import java.util.*;

import javax.xml.transform.*;
import javax.xml.transform.stream.*;

public class TransformerThread extends Thread {

    Templates templates;
    boolean synchronize;

    public static void main(String []args) throws 
TransformerConfigurationException {
        Templates templates = TransformerFactory.newInstance().newTemplates(
            new StreamSource(new File(args[0]))
            );
        Thread []threads = new Thread[5];
        for (int i=0; i<threads.length; ++i) {
            threads[i] = new TransformerThread(
                templates,
                "thread-"+String.valueOf(i+1),
                Boolean.valueOf(args[1]).booleanValue()
                );
            threads[i].start();
        }
        System.out.println("Threads kicked off");
        System.out.flush();
        for (int i=0; i<threads.length; ++i) {
            try {
                threads[i].join();
            }
            catch (InterruptedException e) { /* ignore */}
        }
    }

    public TransformerThread(Templates templates, String name, boolean 
synchronize) {
        super(name);
        this.templates = templates;
        this.synchronize = synchronize;
    }

    public void run() {
        byte []bytes = new String(
            "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" +
            "<foo>\n" +
            "  <property name=\"bar\">bar-value</property>\n" +
            "  <property name=\"bar\">bar-value</property>\n" +
            "  <property name=\"baz\">baz-value</property>\n" +
            "</foo>"
            ).getBytes();

        for (int i=0; i<2500; ++i) {
            try {
                StreamResult result = new StreamResult(new ByteArrayOutputStream
());
                if (synchronize) {
                    synchronized (templates) {
                        templates.newTransformer().transform(
                            new StreamSource(new ByteArrayInputStream(bytes)),
                            result
                            );
                    }
                }
                else {
                    templates.newTransformer().transform(
                        new StreamSource(new ByteArrayInputStream(bytes)),
                        result
                        );
                }
            }
            catch(TransformerException e) {
                e.printStackTrace();
            }
        }
        System.out.println("done: " + getName());
    }
}


xform.xsl:
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
  <xsl:template match="/foo">
    <foo>
      <xsl:for-each select="property[@name != 'baz']">
        <xsl:copy-of select="."/>
      </xsl:for-each>
    </foo>
  </xsl:template>
</xsl:stylesheet>

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