[antlr-interest] Re: C++ is slower than Java?

[keren_jefet]

Thanks for the fast response.
I downloaded and tested the new 2.7.2a2 version, and results are 
completely different: On all tests I run C++ runs faster.
Thanks again,
Keren.


--- In antlr-interest at y..., Ric Klaren <klaren at c...> wrote:
> Hi,
> 
> On Sun, Feb 24, 2002 at 01:23:44PM -0000, keren_jefet wrote:
> > I have tested the java.g example both on Java-generated parser, 
and
> > on Cpp-generated parser (antlr-2.7.1, buildAST=true).
> > Surprisingly, I found out that the Java parser, was significantly
> > faster than the Cpp one, especially when handling long java source
> > files. (sometimes even 600% faster...)
> >
> > How can that be?
> > Is this related to the specific java.g grammar definitions, or 
maybe
> > it is true for all parsers, no matter of the grammar complexity?
> 
> Hmm strange. Ok I had a quick look now. And noted the following:
> 
> Platform specifics:
> 
> ANTLR: antlr 2.7.2a1
> 
> C++:
>   g++ 2.95.3,
>   Sun Ultra-60: Solaris 2.8, 1 Gigabyte of main memory, 450 MHz 
UltraSPARC-II CPU
>   All tests on a local disc.
>   Relevant compiler options: -O2 -DANTLR_SUPPORT_XML -felide-
constructors
>   (yields binary of 1Mb)
> 
> Java:
>   java version "1.2.2"
>   Solaris VM (build Solaris_JDK_1.2.2_07a, native threads, sunwjit)
>   jikes version 1.11 (10 jan 2000) used as javac
> 
> - java.g java.tree.g from 2.7.1 distro. Generated parsers with 
2.7.2a2.
>   Test files the main antlr/java tree.
> - Ported one small change from java version to C++ version.
> - The C++ version of the treewalker barfs on several files. Guess 
there's a
>   bug or something in the 2.7.2a1 C++ codegen or javacodegen. (My 
guess is
>   the first)
> - Removed the files that misparsed tested again. (this makes my 
results
>   quite questionable I know...) But I presume that if there's no 
error
>   reported that the whole thing gets parsed and that the difference 
should
>   be neglectible (then again it might not..)
> 
> Java version comes down to this:
> 
> real       20.9
> user       10.7
> sys         6.6
> 
> C++ version to this:
> 
> real        7.1
> user        6.1
> sys         0.0
> 
> These results are may vary one or two tenth per number between 
runs. So I
> don't see the behaviour you do, not even the slightest indication 
of it.
> You might post some more specifics on your testrig. Feel free to 
mail me
> your testfiles and I'll run them here.
> 
> Ric
> 
> PS Oh yah and I had my xmms still playing Tristania's World of 
Glass album
> which is btw very enjoyable ;)
> --
> -----
+++++*****************************************************+++++++++---
----
>     ---- Ric Klaren ----- klaren at c... ----- +31 53 4893722  ----
> -----
+++++*****************************************************+++++++++---
----
>      Human beings, who are almost unique in having the ability to 
learn
>    from the experience of others, are also remarkable for their 
apparent
>          disinclination to do so. --- Douglas Adams, Last Chance to 
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