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https://issues.apache.org/jira/browse/GROOVY-8019?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Craig White updated GROOVY-8019:
--------------------------------
Description:
While using a Groovy script we came across a strange performance anomaly.
Having the bulk of our script wrapped in an if( true ){} statement as opposed
to an if( 1==1 ){} statement severely degrades performance of the inner part
of the script. Multi-threaded performance is most severely affected. There
appeared to be much more contention running the same script on a 48 core box
with the "if(true)". (took about 100x longer to run 48 copies of these
scripts on their own threads).
The curious aspect of this, is that the 'if' statement is not in the nested
loops, but somehow has negatively affected the compilation / optimization /
byte-code.
Running a Single copy of this script on a 8 core i7 shows quite a performance
hit too... (5000ms vs. 200ms)
The (effective) code to run the script is as follows...
{code}
compiledScript = ((Compilable)engine).compile(scriptString);
result = compiledScript.eval(bindings);
{code}
Here's the script...
{code}
// $script_engine_name=groovy
long sum = 0;
double m = 1;
if( true ) {
System.err.println( "START");
long t0 = System.currentTimeMillis();
for( int j=0; j<1000; j++ ) {
for( int i=0; i<100000; i++ ) {
sum = sum + i;
m = m*i;
}
}
long t1 = System.currentTimeMillis();
System.err.println( "END - " + (t1-t0)+"ms");
}
System.err.println( "Done: "+sum+" "+m );
{code}
was:
While using a Groovy script we came across a strange performance anomaly.
Having the bulk of our script wrapped in an if( true ){} statement as opposed
to an if( 1==1 ){} statement severely degrades performance of the inner part
of the script. Multi-threaded performance is most severely affected. There
appeared to be much more contention running the same script on a 48 core box
with the "if(true)". (took about 100x longer to run 48 copies of these
scripts on their own threads).
The curious aspect of this, is that the 'if' statement is not in the nested
loops, but somehow has negatively affected the compilation / optimization /
byte-code.
Running a Single copy of this script on a 8 core i7 shows quite a performance
hit too... (5000ms vs. 200ms)
The (effective) code to run the script is as follows...
compiledScript = ((Compilable)engine).compile(scriptString);
result = compiledScript.eval(bindings);
Here's the script...
{code}
// $script_engine_name=groovy
long sum = 0;
double m = 1;
if( true ) {
System.err.println( "START");
long t0 = System.currentTimeMillis();
for( int j=0; j<1000; j++ ) {
for( int i=0; i<100000; i++ ) {
sum = sum + i;
m = m*i;
}
}
long t1 = System.currentTimeMillis();
System.err.println( "END - " + (t1-t0)+"ms");
}
System.err.println( "Done: "+sum+" "+m );
{code}
> Strange performance issue using if(true) versus if(1==1)
> --------------------------------------------------------
>
> Key: GROOVY-8019
> URL: https://issues.apache.org/jira/browse/GROOVY-8019
> Project: Groovy
> Issue Type: Bug
> Affects Versions: 2.4.4, 2.4.7
> Environment: Groovy Script Engine in a Java app running on Windows 7
> and Windows Server 2012
> Reporter: Craig White
>
> While using a Groovy script we came across a strange performance anomaly.
> Having the bulk of our script wrapped in an if( true ){} statement as
> opposed to an if( 1==1 ){} statement severely degrades performance of the
> inner part of the script. Multi-threaded performance is most severely
> affected. There appeared to be much more contention running the same script
> on a 48 core box with the "if(true)". (took about 100x longer to run 48
> copies of these scripts on their own threads).
> The curious aspect of this, is that the 'if' statement is not in the nested
> loops, but somehow has negatively affected the compilation / optimization /
> byte-code.
> Running a Single copy of this script on a 8 core i7 shows quite a performance
> hit too... (5000ms vs. 200ms)
> The (effective) code to run the script is as follows...
> {code}
> compiledScript = ((Compilable)engine).compile(scriptString);
> result = compiledScript.eval(bindings);
> {code}
> Here's the script...
> {code}
> // $script_engine_name=groovy
> long sum = 0;
> double m = 1;
> if( true ) {
> System.err.println( "START");
> long t0 = System.currentTimeMillis();
> for( int j=0; j<1000; j++ ) {
> for( int i=0; i<100000; i++ ) {
> sum = sum + i;
> m = m*i;
> }
> }
> long t1 = System.currentTimeMillis();
> System.err.println( "END - " + (t1-t0)+"ms");
> }
> System.err.println( "Done: "+sum+" "+m );
> {code}
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