Switch profiling for better switch performance?

[John Rose]

On Apr 24, 2008, at 11:29 AM, Charles Oliver Nutter wrote:
> I know resources are a problem, but is there any thought going towards
> improving switch performance? I know at least one JRuby team member  
> that
> could provide some pretty unpleasant benchmark results that show the
> pain we're facing.

That would be a great first project for a new hotspot programmer.

The present set of Sun engineers is a couple hundred feet underwater,  
and the upward view shows a number of such optimization projects,  
large and small, floating in the sunlight, out of our present reach.   
We are not limited by our vision, but by our numbers.

Another difficulty is that it generally takes people a year or two to  
get comfortable with the details of the compilers (server and client  
JIT).  But the fastest way in is total immersion (to continue the  
aqueous metaphor).

I personally would enjoy helping someone improve the collection and  
use of profiling information in hotspot, for switches.  Especially if  
it would make bytecode interpreters go faster (most especially, RE  
engines).

The first step is to file a bug report (on bad performance of  
switch), with test code.  The next step is to study the materials on  
contributing to OpenJDK.

http://openjdk.java.net/contribute/

-- John
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