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 <[email protected]>: > >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
ex.rkt
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