[Bese-devel] UCW vs Seaside (and Scheme)

[Waldo Rubinstein]

If you all don't mind a novice question where can I learn more about  
the meaning of xxxx/cc? Is this some CL stuff? Or is this some UCW  
feature? There is definitely a huge performance impact, and I'd like  
to learn more about this.

Thanks,
Waldo

On Sep 4, 2005, at 5:53 AM, Marco Baringer wrote:

> Aleksandar Bakic <a_bakic at yahoo.com> writes:
>
>
>>>> Working properly, at the cost of one or two orders of magnitude
>>>> slowdown in the interpreted code. The interpreted code isn't a
>>>> bottleneck, so don't worry about it.
>>>>
>>
>> I suppose not everything is interpreted. Is it just code wrapped by
>> with-call/cc, defaction and defmethod/cc, or is there more? Any  
>> suggestions on
>> how to structure code to know easily which chunks of code are  
>> interpreted and
>> which ones are compiled?
>>
>
> anything within the body of a with-call/cc is interpreted, this
> includes any macro which wraps with-call/cc, such as:
>
> defun/cc
> defmethod/cc
> defaction
> defentry-point
>
> here's a half backed benchmark (note that this stresses the speed of
> function calls, which in the interpreter are known to be slow):
>
> ARNESI> (defun fib (x)
>           (if (< x 2)
>               1
>               (+ (fib (- x 1))
>                  (fib (- x 2)))))
> FIB
> ARNESI> (time (fib 30))
> (FIB 30) took 386 milliseconds (0.386 seconds) to run.
> Of that, 280 milliseconds (0.280 seconds) were spent in user mode
>          0 milliseconds (0.000 seconds) were spent in system mode
>          106 milliseconds (0.106 seconds) were spent executing  
> other OS processes.
>
> 1346269
> ARNESI> (defun/cc fib/cc (x)
>           (if (< x 2)
>               1
>               (+ (fib/cc (- x 1))
>                  (fib/cc (- x 2)))))
> FIB/CC
> ARNESI> (time (with-call/cc (fib/cc 30)))
> (WITH-CALL/CC (FIB/CC 30)) took 510,689 milliseconds (510.689  
> seconds) to run.
> Of that, 214,840 milliseconds (214.840 seconds) were spent in user  
> mode
>          37,720 milliseconds (37.720 seconds) were spent in system  
> mode
>          258,129 milliseconds (258.129 seconds) were spent  
> executing other OS processes.
> 90,336 milliseconds (90.336 seconds) was spent in GC.
>  2,940,249,976 bytes of memory allocated.
>
> 1346269
> ARNESI>
>
> so it took 510 seconds vs 0.386 (~ 1300 times slower). the real cause
> though is the difference in memory use: 2,940,249,976 bytes (2.73 GB)
> vs. 0. that said, fib doesn't need call/cc, let's compare our fib with
> this:
>
> ARNESI> (time (with-call/cc (fib 30)))
> (WITH-CALL/CC (FIB 30)) took 345 milliseconds (0.345 seconds) to run.
> Of that, 260 milliseconds (0.260 seconds) were spent in user mode
>          0 milliseconds (0.000 seconds) were spent in system mode
>          85 milliseconds (0.085 seconds) were spent executing other  
> OS processes.
>  216 bytes of memory allocated.
>
> 1346269
> ARNESI>
>
> so if you have a piece of code you know to be slow just move it out
> into a seperate function and call that (technically the intepreter
> could do this enough, but it's just not worth the effort).
>
> -- 
> -Marco
> Ring the bells that still can ring.
> Forget the perfect offering.
> There is a crack in everything.
> That's how the light gets in.
>     -Leonard Cohen
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