Subject: C435 JGSI Review Resent-Date: Thu, 30 Sep 1999 23:19:11 -0400 Resent-From: Geoffrey Fox Resent-To: p_gcf@npac.syr.edu Date: Mon, 20 Sep 1999 00:52:03 -0600 From: "David S. Dixon" Organization: Least Squares Software, LLC To: Geoffrey Fox 1. Overall ******** An interesting and well-written article on adding annotation to Java bytecode to improve JIT performance. The motivations for annotation (performance with backward compatibility) are given clearly. The annotation scheme presented seems feasible, being reasonable in scope with easily documented payback. Illustrations of the "virtual register" annotation are quite good, but the proposed annotations for "remove if physical", "swap" and "copy" lack clear illustrations. 2. Comments for Author(s) ********************* Great writing overall. The clarity falls off a bit in section 7 -- I think clearer illustrations of what's going on in the VR location table would help. Consider the second to last sentence of the second paragraph on page 15, starting "However, we can improve this code by annotating to goto bytecode at PC 30..." I don't see anything happening at PC 30. Is there meant to be an illustration here? Did I miss it? Or is it missing? The next paragraph, by the way, is great. Regarding the third paragraph on page 17, beginning "Another JVM developed in a commercial environment is one at IBM Tokyo..." Rather than say "We prove this assertion false..." it would be more correct to say "We prove this statement to be limited to non-annotation-aware JITs" 3. Comments for Editor(s) ******************** None.