[ragel-users] Improving perf of the Java code

[Charles Oliver Nutter]

Yeah, that's kinda what I was thinking. Specifically, my own JVM
language that's a thin layer over JVM bytecode:

https://github.com/headius/bitescript/blob/master/examples/fib.bs

The other though I had was emitting normal Java code that could be
post-processed into a goto...i.e. emit calls like

_label("named label")

_goto("named label")

And post-process the bytecode to use JVM bytecode goto instead.

If we were able to emit something like that, how hard would it be to
get the faster FSM forms ported to Java?

- Charlie

On Wed, Dec 21, 2011 at 11:02 AM, Conrad Steenberg
<conrad.steenberg at gmail.com> wrote:
> Hi Charlie,
>
> I addition to looking at a bytecode generator, you might also look at
> generating code for another JVM language that does have support for
> goto. That language might even be C, if you can get the resulting code
> to generate the JRuby objects you need.
>
> See http://en.wikipedia.org/wiki/List_of_JVM_languages
>
> On Wed, 2011-12-21 at 00:30 -0600, Charles Oliver Nutter wrote:
>> Hello!
>>
>> I work on JRuby, the Ruby implementation for the JVM. As you may know,
>> Ruby users have latched on to Ragel for a number of parser tasks, such
>> as json, http, various markup languages, and so on.
>>
>> I have spent the last day trying to optimize a Ragel-generated json
>> parser used as an extension to JRuby, and despite my best efforts I
>> can't get it more than about 2x slower than the version for C Ruby.
>> This is especially poor considering the Ruby code that surrounds it
>> should run significantly faster on JRuby, and it still doesn't make up
>> the gap.
>>
>> I'm wondering what, if anything, can be done to improve the
>> performance of the generated Java code. I notice that Java is only
>> supported in the simplest output form, presumably because of the lack
>> of "goto". I'm interested in exploring options to bring the Java code
>> up to par with the generated code for other languages, perhaps by
>> implementing it using raw JVM bytecode (using some assembly-like
>> format like BiteScript or Jasmin) or by post-processing the compiled
>> result to insert true gotos.
>>
>> Any pointers on this? Any prior work or tips?
>>
>> - Charlie
>>
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>
>
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