Top 5

[Sascha Katzner]

Benji Smith wrote:
> Actually, when it comes to string processing, D is decidedly *not* a 
> "performance language".
> 
> Compared to...say...Java (which gets a bum rap around here for being 
> slow), D is nothing special when it comes to string processing speed.
> 
> I've attached a couple of benchmarks, implemented in both Java and D 
> (the "shakespeare.txt" file I'm benchmarking against is from the 
> Gutenburg project. It's about 5 MB, and you can grab it from here: 
> http://www.gutenberg.org/dirs/etext94/shaks12.txt )
> 
> In some of those benchmarks, D is slightly faster. In some of them, Java 
> is a lot faster. Overall, on my machine, the D code runs in about 12.5 
> seconds, and the Java code runs in about 2.5 seconds.
> 
> Keep in mind, all java characters are two-bytes wide. And you can't 
> access a character directly. You have to retrieve it from the String 
> object, using the charAt() method. And splitting a string creates a new 
> object for every fragment.
> 
> I admire the goal in D to be a performance language, but it drives me 
> crazy when people use performance as justification for an inferior 
> design, when other languages that use the superior design also 
> accomplish superior performance.

I think your benchmark is not very meaningful. Without going into 
implementation details of Tango (because I don't use Tango) here are 
some notes:

- The D version uses UTF8 strings whereas the Java version uses 
"wanna-be" UTF16 (Java has a lot of problems with surrogates). This 
means you are comparing apples with pears (D has to *parse* an UTF8 
string and Java simply uses an wchar array without proper surrogate 
handling in *many* cases).

- At least in runCharIterateTest() you also convert the D UTF8 string 
also additionally into an UTF32 string, in the Java version you did not 
do this.

- The StringBuilder in the Java version is *much* faster because it 
doesn't have to allocate a new memory block in each step. You can use a 
similar class in D too, without the need of a special string class/object.

...

LLAP,
Sascha