On Thu, Feb 3, 2011 at 12:34 PM, Mirko Vukovic <
mirko.vukovic@gmail.com> wrote:
> Hello,
>
> I was wondering whether optimization can help grid-map's performance. (But
> I really have not done
> much optimizing). So, I timed the following two functions which map `sin'
> over a really large grid:
>
> (in-package :grid)
>
> (defun optimized (arg)
> (grid:map-grid :source arg
> :element-function
> #'(lambda (arg)
> (declare
> (optimize (speed 3) (safety 0) (debug 0))
> (double-float arg))
> (the double-float (sin arg))))
> (values))
>
> (defun unoptimized (arg)
> (grid:map-grid :source arg
> :element-function
> #'(lambda (arg)
> (sin arg)))
> (values))
>
> (progn
> (defvar *arg* nil)
> (setf *arg* (grid:make-grid '((foreign-array 300000) double-float)
> :initial-element 1d0))
> nil)
>
> On 64bit linux & SBCL, compilation of the optimized routine generate the
> following notes
> that I don't understand:
>
> ; note: unable to avoid inline argument range check
> ; because the argument range (DOUBLE-FLOAT) was not within 2^63
>
> ; #'(LAMBDA (GRID::ARG)
> ; (DECLARE (OPTIMIZE (SPEED 3) (SAFETY 0) (DEBUG 0))
> ; (DOUBLE-FLOAT GRID::ARG))
> ; (THE DOUBLE-FLOAT (SIN GRID::ARG)))
> ;
> ; note: doing float to pointer coercion (cost 13) to "<return value>"
>
> Timing both routines gives very similar results:
>
> GRID> (time (unoptimized *arg*))
> Evaluation took:
> 0.112 seconds of real time
> 0.111983 seconds of total run time (0.110983 user, 0.001000 system)
> [ Run times consist of 0.004 seconds GC time, and 0.108 seconds non-GC
> time. ]
> 100.00% CPU
> 335,890,827 processor cycles
> 19,202,048 bytes consed
>
> GRID> (time (optimized *arg*))
> Evaluation took:
> 0.113 seconds of real time
> 0.112983 seconds of total run time (0.111983 user, 0.001000 system)
> [ Run times consist of 0.003 seconds GC time, and 0.110 seconds non-GC
> time. ]
> 100.00% CPU
> 337,194,558 processor cycles
> 19,202,032 bytes consed
>
> Any ideas how to properly optimize the code?
>
> Thanks,
>
> Mirko
>
>
