[antlr-interest] Re: Generated C++ Parser Performance

[lgcraymer]

Ruslan--

The lexer is the part of ANTLR most in need of optimization--many very
small methods (a likely source of differences), unoptimized memory
usage, and so on.  Function call overhead is less likely to be a
problem in the parser--function bodies are larger--although memory
management could still be an issue.  Object creation/destruction could
also be a contributing factor, but that would show up as method
overhead--C++ does a lot of object create/delete in method calls
because of the mix of call by reference and call by value that occurs
with little programmer awareness.

Anyway, call it an educated guess.  I could be wrong; however,
replacing the lexer is an easy way to improve performance.

--Loring


--- In antlr-interest at yahoogroups.com, Ruslan Zasukhin <sunshine at p...>
wrote:
> On 3/16/04 8:48 AM, "lgcraymer" <lgc at m...> wrote:
> 
> > I'd bet on the lexer then.  The only other likely sources of slowdown
> > memory are memory management--a custom allocator for ASTs might
> > help--and exceptions (syntactic predicates).  Ric may have some other
> > suggestions.
> 
> Lorin,
> 
> Why you say this is lexer fault?
> Java parser uses the same ANTLR lexer, yes?
> 
> So why C++ parser is slower of Java ?!
> 
> Sounds not pleasant.
> 
> 
> Oh guys:    "I feel the need...the need for speed"
> 
> -----------------------
> Terrence, Rick,
> 
> Speed should be the highest priority for ANTLR 3.0 IMHO.
> 
> You should develop 
>     -- regression tests
>     -- regression BENCHMARKS
>     -- run benchmarks with profiles
>         improve everything you can improve.
> 
> 
> 
> -- 
> Best regards,
> Ruslan Zasukhin      [ I feel the need...the need for speed ]
> -------------------------------------------------------------
> e-mail: ruslan at p...
> web: http://www.paradigmasoft.com
> 
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