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I've profiled an editing session, where I manipulate large-ish Java files (around 20k lines, lots of overloads, Javadoc, etc.). For the record, these are some examples of such files: - https://github.com/jOOQ/jOOQ/blob/master/jOOQ/src/main/java/org/jooq/impl/DSL.java - https://github.com/jOOQ/jOOQ/blob/master/jOOQ/src/main/java/org/jooq/DSLContext.java The profiler session showed that there seems to be a hot loop that calls: org.eclipse.jdt.internal.ui.javaeditor.SemanticHighlightingReconciler.PositionCollector.addPosition(int offset, int length, Highlighting highlighting) In this method, we loop over an ArrayList and access elements via List.get(i): --------------------------------------------------------------- Stack Trace Sample Count Percentage(%) java.util.ArrayList.elementData(int) 545 10.807 java.util.ArrayList.get(int) 545 10.807 org.eclipse.jdt.internal.ui.javaeditor.SemanticHighlightingReconciler$PositionCollector.addPosition(int, int, SemanticHighlightingManager$Highlighting) 544 10.787 org.eclipse.jdt.internal.ui.javaeditor.SemanticHighlightingReconciler$PositionCollector.visit(SimpleName) 544 10.787 org.eclipse.jdt.core.dom.SimpleName.accept0(ASTVisitor) 544 10.787 org.eclipse.jdt.core.dom.ASTNode.accept(ASTVisitor) 544 10.787 org.eclipse.jdt.core.dom.ASTNode.acceptChildren(ASTVisitor, ASTNode$NodeList) 276 5.473 org.eclipse.jdt.core.dom.ArrayInitializer.accept0(ASTVisitor) 198 3.926 org.eclipse.jdt.core.dom.MethodInvocation.accept0(ASTVisitor) 50 0.991 org.eclipse.jdt.core.dom.ClassInstanceCreation.accept0(ASTVisitor) 28 0.555 org.eclipse.jdt.core.dom.ASTNode.acceptChild(ASTVisitor, ASTNode) 268 5.314 org.eclipse.jdt.core.dom.SingleVariableDeclaration.accept0(ASTVisitor) 128 2.538 org.eclipse.jdt.core.dom.MethodInvocation.accept0(ASTVisitor) 74 1.467 org.eclipse.jdt.core.dom.SingleMemberAnnotation.accept0(ASTVisitor) 27 0.535 org.eclipse.jdt.core.dom.MarkerAnnotation.accept0(ASTVisitor) 16 0.317 org.eclipse.jdt.core.dom.CastExpression.accept0(ASTVisitor) 8 0.159 org.eclipse.jdt.core.dom.QualifiedName.accept0(ASTVisitor) 6 0.119 org.eclipse.jdt.core.dom.InfixExpression.accept0(ASTVisitor) 3 0.059 org.eclipse.jdt.core.dom.ArrayAccess.accept0(ASTVisitor) 2 0.04 org.eclipse.jdt.core.dom.VariableDeclarationFragment.accept0(ASTVisitor) 2 0.04 org.eclipse.jdt.core.dom.ReturnStatement.accept0(ASTVisitor) 1 0.02 org.eclipse.jdt.core.dom.InstanceofExpression.accept0(ASTVisitor) 1 0.02 --------------------------------------------------------------- If the fRemovedPositions list could be replaced by an array, this loop would perform a lot faster. An alternative might be to loop over the List with a ListIterator. Of course, these are only suggestions regarding the improvement of the hot loop itself. Perhaps, there is a better algorithm that would avoid this loop from being so hot. Let me know if you need any additional profiling information, and I will happily provide it. Also, it appears that this might be the same issue as: https://bugs.eclipse.org/bugs/show_bug.cgi?id=19133
(In reply to Lukas Eder from comment #0) > I've profiled an editing session, where I manipulate large-ish Java files > (around 20k lines, lots of overloads, Javadoc, etc.). For the record, these > are some examples of such files: > > - > https://github.com/jOOQ/jOOQ/blob/master/jOOQ/src/main/java/org/jooq/impl/DSL.java > > - > https://github.com/jOOQ/jOOQ/blob/master/jOOQ/src/main/java/org/jooq/DSLContext.java Can you attach a self-contained test project?
It's hard to track it down to a single class or item. I can reproduce this issue when checking out the whole project afresh from GitHub, and then importing it as a new project into Eclipse: https://github.com/jOOQ/jOOQ/tree/master/jOOQ From then on, when I open the org.jooq.impl.DSL class, modify it (e.g. by adding whitespace, copy pasting things around, etc.), and saving it, I can see various hot items in a profiler session, among which the call to PositionCollector.addPosition().
This bug hasn't had any activity in quite some time. Maybe the problem got resolved, was a duplicate of something else, or became less pressing for some reason - or maybe it's still relevant but just hasn't been looked at yet. If you have further information on the current state of the bug, please add it. The information can be, for example, that the problem still occurs, that you still want the feature, that more information is needed, or that the bug is (for whatever reason) no longer relevant. -- The automated Eclipse Genie.
