0

I am trying to use ASM for my project and hit a performance issue where I am trying to get required object using a static method and its called like 1000 times

visitor.visitMethodInsn(Opcodes.INVOKESTATIC, TrackingConstants.TO_HELPER_CLASS, "getRTTDObject",TrackingConstants.TO_HELPER_GET_CLIENT_METHOD_DESC);

visitor.visitMethodInsn(Opcodes.INVOKEINTERFACE, TrackingConstants.CLIENT_INTERFACE_CLASS, "getPattern",TrackingConstants.CLIENT_INTERFACE_CLASS_GETPATTERN_METHOD_DESC);

This first call is causing me overhead(where I get required object and pass to next line for performing "getPattern" on the object.During investigation I realized that the object which I am trying to retrieve via the static method is available with me from the starting itself so if I was able to push that Java object onto stack and avoid the static calls I wouldn't not face any performance issues.

I tried couple of ways with no luck and finally tried to create new Field of the object but get an IllegalArgumentException similar to this post Creating a new field with asm 4 after going through the link I realized that we need write code to create the object and can't directly use existing object.

So is there no way I can load my existing Java object onto stack (I guess it will already be on stack, is there a way I can use it) and perform required operations instead of using Static call to get it? Is there a way I can achieve it?

Improve this question
6
  • Have you determined that this is actually a performance bottleneck? Have you determined that the JVM isn't caching/inlining this already? Commented Oct 7, 2013 at 13:14
  • Hi Antimony,No i use profiler to identify where bottle neck is and found that the static calls being made are consuming around 1.8%.How can i know if caching/inlining is done?You meant these repeated static calls needs to be cached and that is supposed to be taken care by JVM?? Commented Oct 7, 2013 at 13:22
  • Well the JVM is supposed to do stuff like that automatically. Not sure why it isn't in this case. Commented Oct 7, 2013 at 17:32
  • I will check with some of the JVM folks i know.Coming back to my question so there is no way i can load existing java object to avoid static calls??i have a getter method in my methodadapter which gives me the java object is.. there a way i can load this to my current stack which i am trying to populate using ASM?i came to know from your earlier reply that visitLdcInsn wont work here... Commented Oct 8, 2013 at 15:33
  • The only ways to get an existing nonconstant object are from a method call or field access. But if the method or field is simple enough, it should be inlined anyway. Commented Oct 8, 2013 at 19:46

1 Answer 1

Reset to default
1

Once the object is on the stack (presumably after you call your static method the first time), you can:

  1. Emit a DUP instruction to duplicate the value already on the stack each time it is needed. This is probably the most performant option, but it requires you to craft your bytecode in such a way that the value will always be at/near the top of the stack when you need it. There are a few variants of the DUP instruction to choose from, each with different behavior; see the JVM Specification §6.5 for details.

  2. Call the static method once, then store the result in a temporary variable (use one of the ASTORE instruction variants). Push it onto the stack when it's needed by using the corresponding ALOAD variant.

Depending on the structure of your method, you may also combine these techniques (load from a temporary local, DUP as necessary, do something unrelated, repeat, etc.).

Improve this answer
Sign up to request clarification or add additional context in comments.

Comments

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.