[racket] Optimization

 I have "debugging & profiling" on.

Disable debugging. Now have all zeroes :-)
 cpu time: 0 real time: 0 gc time: 0

I will check with optimization. If find something strange, I'll write.


Mon, 16 Jun 2014 08:58:16 +0100 от Matthew Flatt <mflatt at cs.utah.edu>:
>Hm... I'm not able to get anything like the results you're reporting.
>When I run the enclosed program via `racket` on the command line, I get
>
> cpu time: 3 real time: 3 gc time: 0
> cpu time: 3 real time: 3 gc time: 0
> cpu time: 2 real time: 2 gc time: 0
> cpu time: 3 real time: 3 gc time: 0
> cpu time: 5 real time: 5 gc time: 3
> cpu time: 2 real time: 2 gc time: 0
> cpu time: 2 real time: 2 gc time: 0
> cpu time: 2 real time: 2 gc time: 0
> cpu time: 4 real time: 4 gc time: 1
>
>Running in DrRacket gives messier results, such as
>
> cpu time: 17 real time: 10 gc time: 0
> cpu time: 19 real time: 22 gc time: 0
> cpu time: 7 real time: 7 gc time: 0
> cpu time: 15 real time: 8 gc time: 0
> cpu time: 14 real time: 10 gc time: 0
> cpu time: 10 real time: 10 gc time: 0
> cpu time: 7 real time: 6 gc time: 0
> cpu time: 7 real time: 7 gc time: 0
> cpu time: 23 real time: 29 gc time: 15
>
>or
>
> cpu time: 6 real time: 6 gc time: 0
> cpu time: 5 real time: 4 gc time: 0
> cpu time: 58 real time: 57 gc time: 49
> cpu time: 6 real time: 5 gc time: 0
> cpu time: 5 real time: 4 gc time: 0
> cpu time: 6 real time: 6 gc time: 0
> cpu time: 5 real time: 5 gc time: 0
> cpu time: 5 real time: 4 gc time: 0
> cpu time: 15 real time: 16 gc time: 9
>
>I'm using v6.0.1.12 on Mac OS X 64-bit on a MacBook Pro. Version 6.0.1
>on the same machine seems to produce the same sorts of results.
>
>Any idea what might be different?
>
>At Mon, 16 Jun 2014 11:44:41 +0400, Roman Klochkov wrote:
>>  (define data (for/list ([x 100000]) x))
>> 
>> (time (begin0 (void) (run2 data)))
>> (time (begin0 (void) (run1 data)))
>> 
>> 3 times run1, then 3 times run2, then again 3 times run1.
>> 
>> Results are stable.
>> 
>> Mon, 16 Jun 2014 08:28:10 +0100 от Matthew Flatt < mflatt at cs.utah.edu >:
>> >I'd expect them to run nearly the same due to inlining and constant
>> >propagation. If I save your program to "ex.rkt" and use
>> >
>> > raco make ex.rkt
>> > raco decompile ex.rkt
>> >
>> >the the output looks almost the same for both functions.
>> >
>> >There's a lot of allocation in these programs, of course, and that's
>> >going to make benchmarking relatively tricky. How are you timing the
>> >functions, and does it matter whether you `run1` or `run2` first?
>> >
>> >At Mon, 16 Jun 2014 11:16:25 +0400, Roman Klochkov wrote:
>> >>  Strange.
>> >> 
>> >> #lang racket
>> >> (define (test1 x y)
>> >>   (if x
>> >>     (+ y 1)
>> >>     (- y 1)))
>> >> (define (test2 x)
>> >>   (if x
>> >>     (λ (y) (+ y 1))
>> >>     (λ (y) (- y 1))))
>> >> (define (run1 data)
>> >>   (map (λ (x) (test1 #t x)) data))
>> >> (define (run2 data)
>> >>   (map (λ (x) ((test2 #t) x)) data)) I expect, that run2 should be faster, 
>> >> because (test2 #t) returns const (lambda (y) (+ y 1)) and shouldn't be 
>> checked 
>> >> on every iteration.
>> >> 
>> >> But in reality (time ...) gives 219 for run1 and 212 for run2. run2 is 1.5 
>> >> times slower!
>> >> 
>> >> Why so?
>> >> 
>> >> 
>> >> -- 
>> >> Roman Klochkov____________________
>> >>   Racket Users list:
>> >>  http://lists.racket-lang.org/users
>> 
>> 
>> -- 
>> Roman Klochkov
>> ____________________
>>   Racket Users list:
>>  http://lists.racket-lang.org/users


-- 
Roman Klochkov
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