From: Siddhesh Poyarekar <siddhesh-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: "Michael Kerrisk (man-pages)"
<mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: "Manuel López-Ibáñez"
<lopezibanez-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
"GNU C Library"
<libc-alpha-9JcytcrH/bA+uJoB2kUjGw@public.gmane.org>
Subject: Re: [patch] pow.3: Add note on performance characteristics of pow
Date: Fri, 17 Oct 2014 13:28:45 +0530 [thread overview]
Message-ID: <20141017075845.GL1552@spoyarek.pnq.redhat.com> (raw)
In-Reply-To: <5440A816.8000002-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
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On Fri, Oct 17, 2014 at 07:24:38AM +0200, Michael Kerrisk (man-pages) wrote:
> > diff --git a/man3/pow.3 b/man3/pow.3
> > index d0a2ea8..3d2151a 100644
> > --- a/man3/pow.3
> > +++ b/man3/pow.3
> > @@ -320,6 +320,17 @@ The variant returning
> > also conforms to
> > SVr4, 4.3BSD, C89.
> > .SH BUGS
> > +On 64-bits,
> > +.\"
> > +.\" https://sourceware.org/bugzilla/show_bug.cgi?id=13932
> > +.BR pow ()
> > +may be more than 10,000 times slower for some inputs than for other nearby
>
> I plan to change "some" to "some (rare)". Sound okay? The point is not to
> worry people that this is a problem that is commonly encountered. (Or is it?)
Rare is OK, these points don't occur very frequently.
> > +inputs. The inputs that produce such behavior are different for
> > +.BR powf (),
> > +.BR pow ()
> > +and
> > +.BR powl ().
> > +
The slow fallback is only taken for pow, not powf or powl.
Siddhesh
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next prev parent reply other threads:[~2014-10-17 7:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-16 23:51 [patch] pow.3: Add note on performance characteristics of pow Manuel López-Ibáñez
[not found] ` <CAESRpQDx5TfgfRp1q69NiuCB5ve8+fR1NC2up9h5LOkogMKkqQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-17 5:24 ` Michael Kerrisk (man-pages)
[not found] ` <5440A816.8000002-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-10-17 7:58 ` Siddhesh Poyarekar [this message]
[not found] ` <20141017075845.GL1552-EBXREzpM9Zo4v7BKUif6HKfLeoKvNuZc@public.gmane.org>
2014-10-17 13:51 ` Manuel López-Ibáñez
[not found] ` <CAESRpQB5K9U1sBreXUrNa4tPB69cwxC+fdu1bUr5BkU-dtxJMQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-30 23:30 ` Manuel López-Ibáñez
2014-11-11 12:58 ` Michael Kerrisk (man-pages)
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