[debbugs-tracker] bug#17147: closed (Performance regression by 3000000% for evaluating "and" form)

[GNU bug Tracking System]

Your message dated Wed, 04 Jun 2014 21:09:23 -0400
with message-id <address@hidden>
and subject line Re: bug#17147: [PATCH] Add versions of and/or avoiding O(n^2) 
argument matching
has caused the debbugs.gnu.org bug report #17147,
regarding Performance regression by 3000000% for evaluating "and" form
to be marked as done.

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-- 
17147: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=17147
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> --- Begin Message ---
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> Subject: 
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> Performance regression by 3000000% for evaluating "and" form
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> Date: 
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> Mon, 31 Mar 2014 11:58:00 +0200
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> The following program goes from 2.3ms execution time to 80s execution
> time when going from Guile-1.8 to current master.
>
> (use-modules (srfi srfi-19))
> (define start-time (current-time))
> (primitive-eval (cons 'and (make-list 10000 #f)))
> (display (time-difference (current-time) start-time))
>
>
> With Guile-2.0.9 (Ubuntu package), it crashes with
> Backtrace:
> In ice-9/psyntax.scm:
> 2683: 19 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 18 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 17 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 16 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 15 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 14 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 13 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 12 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 11 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 10 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 9 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 8 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 7 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 6 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 5 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 4 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 3 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 2 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 1 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
> 2683: 0 [match-each-any (#f #f #f ...) ((#f top) shift) ...]
>
> ice-9/psyntax.scm:2683:37: In procedure match-each-any:
> ice-9/psyntax.scm:2683:37: Throw to key `vm-error' with args `(vm-run "VM: 
> Stack overflow" ())'.
>
> which might give a clue as to where Guile-v2 is spending all its time.
>
> -- 
> David Kastrup
>
> --- End Message ---
> --- Begin Message ---
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>
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> Subject: 
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> Re: bug#17147: [PATCH] Add versions of and/or avoiding O(n^2) argument matching
>
>
>
>
> Date: 
>
> Wed, 04 Jun 2014 21:09:23 -0400
>
>
>
>
> User-agent: 
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> Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux)
>
>
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>
> David Kastrup <address@hidden> writes:
>
> > Fixes <http://bugs.gnu.org/17147>
> >
> > * module/ice-9/boot-9.scm (and, or): Add syntax rules that only do one
> >   pattern matching operation per and/or rather than per argument.
>
> Thanks, but I ended up simply changing the macros to dotted tail
> patterns.  It's commit 1ea8954814d124b995f2296bc6aec92adb566bc1.
>
> I'm closing this bug now.
>
>       Mark
>
>
> --- End Message ---