[racket] Optimization

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
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