Hmph. I would expect TR to perform as fast as 'unsafe'.
On Nov 4, 2012, at 7:40 PM, Matthew Flatt wrote: > 2668 msecs when I declare `cycle-length' as `(Integer -> Integer)' and > change `(even? n)' to `else', or 2809 msecs if I add `[else 0]' instead > of changing `(even? n)'. > > At Sun, 4 Nov 2012 18:30:21 -0600, Robby Findler wrote: >> And just to complete the list, how does the TR version fare? >> >> Robby >> >> On Sun, Nov 4, 2012 at 6:26 PM, Matthew Flatt <mfl...@cs.utah.edu> wrote: >>> Thanks! >>> >>> Sometimes, a x3 difference means that we're missing a straightforward >>> opportunity in performance, and that was the case here. The Racket >>> program spent most of its time in generic `/' by pessimistically >>> expecting a non-integer result. >>> >>> I've adjusted the JIT to optimistically compute and check a fixnum >>> result for a division of fixnums, and then the example runs about four >>> times as fast on my machine: >>> >>> Old Racket: 12589 msec >>> New Racket: 3850 msec >>> Racket with `quotient': 3851 msec [old or new is the same] >>> SBCL: 5553 msec >>> SBCL, unsafe fixnum: 2692 msec >>> New Racket, in module: 2823 msec >>> Racket, unsafe fixnum: 2405 msec [uses `fxquotient'] >>> >>> At Sun, 4 Nov 2012 15:54:51 +0000 (UTC), daniel rupistraliz wrote: >>>> >>>> >>>> racket: >>>> Welcome to Racket v5.2.1. >>>>> (define (cycle-length n) >>>> (cond >>>> [(= n 1) >>>> 1] >>>> [(odd? n) >>>> (add1 (cycle-length (add1 (* 3 n))))] >>>> [(even? n) >>>> (add1 (cycle-length (/ n 2)))])) >>>> >>>> (time (for ([i (in-range 1 1000000)]) >>>> (cycle-length i))) >>>>> >>>> cpu time: 15016 real time: 15018 gc time: 0 >>>> >>>> sbcl: >>>> >>>> (defun cycle-length(n) >>>> (cond ((= n 1) 1) >>>> ((oddp n) (1+ (cycle-length (1+ (* 3 n))))) >>>> ((evenp n) (1+ (cycle-length (/ n 2)))))) >>>> >>>> >>>> * (time (loop for i from 1 to 1000000 do (cycle-length i))) >>>> >>>> Evaluation took: >>>> 6.192 seconds of real time >>>> 6.192387 seconds of total run time (6.192387 user, 0.000000 system) >>>> 100.00% CPU >>>> 14,496,643,427 processor cycles >>>> 0 bytes consed >>>> >>>> >>>> With optimizations: >>>> >>>> (defun cycle-length(n) >>>> (declare (fixnum n) >>>> (ftype (function (fixnum) fixnum) cycle-length) >>>> (optimize (speed 3) (safety 0) (compilation-speed 0))) >>>> (cond ((= n 1) 1) >>>> ((oddp n) (the fixnum (1+ (cycle-length >>>> (the fixnum (1+ (the fixnum (* 3 n)))))))) >>>> ((evenp n) (cycle-length (the fixnum (/ n 2)))))) >>>> >>>> CL-USER> (time (loop for i from 1 to (expt 10 6) do (cycle-length i))) >>>> Evaluation took: >>>> 3.515 seconds of real time >>>> 3.524220 seconds of total run time (3.524220 user, 0.000000 system) >>>> 100.26% CPU >>>> 8,228,949,701 processor cycles >>>> 33,008 bytes consed >>>> >>>> So racket = 15 seconds >>>> sbcl = 6 seconds >>>> sbcl optimized = 3.5 seconds. >>>> >>>> >>>> ____________________ >>>> Racket Users list: >>>> http://lists.racket-lang.org/users >>> ____________________ >>> Racket Users list: >>> http://lists.racket-lang.org/users > ____________________ > Racket Users list: > http://lists.racket-lang.org/users
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