[JSR308] Annotations for worst-case execution time

Eugene Kuleshov eu at javatx.org
Tue Jan 30 01:25:47 EST 2007


  It is good that you brought that up. Expanding annotations to allow 
them on statements or blocks is in JSR 308 scope as stated here 

  I am working on a short memo about Java language and bytecode 
representation of the code block level annotations and hoping to send it 
in a day or two.


Trevor Harmon wrote:
> Good to see this list up and running!
> I'm very interested in the progress of JSR-308 because I'm hoping it 
> will eventually allow worst-case execution time (WCET) annotations in 
> Java. I'm actually having a paper published at WPDRTS [1] on that very 
> topic: "Toward a Unified Standard for Worst-Case Execution Time 
> Annotations in Real-Time Java." The last couple of pages talk all 
> about the (potential) relationship between WCET annotations and 
> JSR-308. I don't think IEEE copyright allows me to distribute the 
> paper here, so let me summarize.
> WCET tools for Java use entirely different conventions for 
> annotations, and no tool has yet to standardize on Java's own 
> annotation mechanism. The reason, unfortunately, is that Java 
> annotations are simply too limited. For instance, one of the main 
> reasons you'd want annotations for WCET is to specify loop bounds, but 
> Java annotations aren't even allowed on loops.
> However, there definitely seems to be support for the idea of 
> expanding annotations to allow them in places other than method and 
> variable definitions. In fact, Intel's comment attached to its vote 
> for JSR-308 says:
> "This note confirms our understanding that the scope of the JSR 
> includes providing for annotations on loops and blocks if the Expert 
> Group decides to include that after evaluation. The JSR itself should 
> be updated to make it clear this is in the scope."
> I'm curious to know how far the Expert Group has gone in evaluating 
> Intel's comment. To my knowledge, no one is actually working on 
> implementing the idea. That's why I'm currently studying the javac 
> sources (thank you Sun for open-sourcing Java!) to see how annotations 
> on loops, and possibly other blocks, could be implemented. With this 
> effort, I'm hoping that by the time JDK 7 rolls around, Java's 
> annotation standard will finally be suitable for WCET analysis.
> Any thoughts? Thanks!
> Trevor
> [1] http://wpdrts07.ewi.utwente.nl/
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