UserGuide:Tips_And_Tricks - nimakarimipour/WALAWiki GitHub Wiki
title: UserGuide:Tips And Tricks permalink: /UserGuide:Tips_And_Tricks/
Performance Tips
Heap Size
Use -XmxM to set the heap size to n megabytes. Use
-verbose:gc to see if it looks like the VM is in the GC region of
discontent.
Want to get an idea where memory is going? Check out the HeapTracer utility. It's slow, but I find it useful.
Libraries
Many analyses (e.g. call graph construction) may run dramatically faster when analyzing earlier versions (e.g. 1.4) of the JDK, since 5.0+ libraries introduce various sorts of pollution that we haven't tracked down yet. You may want to prototype your analysis against a 1.4 JDK, and then move up to a later version, perhaps using an Exclusions file later to recover lost performance.
Exclusions File
WALA supports an XML-based exclusions file, which tells WALA to ignore certain classes or packages. Using an exclusions file can drastically speed up analysis, although of course introduces potential unsoundness.
For example, you can use the following code (from
CallGraphTestUtil)
to build an analysis scope that excludes classes based on an exclusions
file.
public static AnalysisScope makeJ2SEAnalysisScope(String scopeFile, String exclusionsFile) {
AnalysisScope scope = AnalysisScopeReader.read(scopeFile, exclusionsFile, MY_CLASSLOADER);
return scope;
}
For a client that uses this, see the
[http://wala.sourceforge.net/javadocs/com.ibm.wala.core.tests/com/ibm/wala/core/tests/callGraph/CallGraphTest.html#testPrimordial()
CallGraphTest.testPrimordial()] unit test.
Here are the contents of
GUIExclusions.txt,
an exclusions file which tells WALA to ignore
AWT-related classes. When using
these exclusions, WALA pretends that classes from java.awt don't
exist.
java\/awt\/.*
javax\/swing\/.*
sun\/awt\/.*
sun\/swing\/.*
Other Issues
Something seem too slow? Let us know how to reproduce the problem. Maybe we'll fix it.