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Re: [Chicken-users] numbers egg slow?
From: |
Daishi Kato |
Subject: |
Re: [Chicken-users] numbers egg slow? |
Date: |
Thu, 06 Oct 2005 15:47:26 +0900 |
User-agent: |
Wanderlust/2.15.1 (Almost Unreal) Emacs/21.4 Mule/5.0 (SAKAKI) |
It was too late... Thanks a lot for your examples of measureing.
I will try it a little bit more. --daishi
At Thu, 06 Oct 2005 01:29:08 -0500,
Alex Shinn wrote:
> You have to be careful what you're measuring. Inside the loop you
> repeatedly call expt, which is slower not only because it makes many
> more checks than before, such as checking the types and signs of the
> arguments, but because it checks the fixnum case last.
>
> If you bind the result once outside the loop you'll see the time using
> fx+ (and also fx> to be sure we're comparing the same thing) is indeed
> exactly the same:
>
> $ csi -eval '(let ((2^17 (expt 2 17)))(gc)(time (let loop ([i 0]) (or (fx> i
> 2^17) (loop (fx+ i 1))))))'
> 0.313 seconds elapsed
> 0 seconds in (major) GC
> 31 mutations
> 1285 minor GCs
> 0 major GCs
>
> $ csi -R numbers -eval '(let ((2^17 (expt 2 17)))(gc)(time (let loop ([i 0])
> (or (fx> i 2^17) (loop (fx+ i 1))))))'
> 0.313 seconds elapsed
> 0 seconds in (major) GC
> 31 mutations
> 1285 minor GCs
> 0 major GCs
>
> Now let's compare the time of the generic numbers + and normal +:
>
> $ csi -eval '(let ((2^17 (expt 2 17)))(gc)(time (let loop ([i 0]) (or (> i
> 2^17) (loop (+ i 1))))))'
> 0.325 seconds elapsed
> 0 seconds in (major) GC
> 31 mutations
> 1289 minor GCs
> 0 major GCs
>
> $ csi -R numbers -eval '(let ((2^17 (expt 2 17)))(gc)(time (let loop ([i 0])
> (or (> i 2^17) (loop (+ i 1))))))'
> 0.454 seconds elapsed
> 0.002 seconds in (major) GC
> 31 mutations
> 58 minor GCs
> 1 major GCs
>
> 0.454 vs 0.325, or about 1.4x slower when using the full number tower.
>
> --
> Alex
- Re: [Chicken-users] numbers egg slow?, felix winkelmann, 2005/10/03
- Re: [Chicken-users] numbers egg slow?, Daishi Kato, 2005/10/06
- Re: [Chicken-users] numbers egg slow?, Alex Shinn, 2005/10/06
- Re: [Chicken-users] numbers egg slow?,
Daishi Kato <=
- Re: [Chicken-users] numbers egg slow?, Daishi Kato, 2005/10/06
- Re: [Chicken-users] numbers egg slow?, Daishi Kato, 2005/10/06
- Re: [Chicken-users] numbers egg slow?, Alex Shinn, 2005/10/07
- Re: [Chicken-users] numbers egg slow?, Daishi Kato, 2005/10/12
- Re: [Chicken-users] numbers egg slow?, Daishi Kato, 2005/10/12
- Re: [Chicken-users] numbers egg slow?, Alex Shinn, 2005/10/13