From: Szabolcs Nagy <nsz@port70.net>
To: musl@lists.openwall.com
Subject: Re: Wrong info in libc comparison
Date: Wed, 13 Sep 2017 21:25:29 +0200 [thread overview]
Message-ID: <20170913192528.GA15263@port70.net> (raw)
In-Reply-To: <20170913185106.ddbgztckagdojcdd@voyager>
* Markus Wichmann <nullplan@gmx.net> [2017-09-13 20:51:06 +0200]:
> On Wed, Sep 13, 2017 at 02:10:10PM -0400, Rich Felker wrote:
> > I'm not sure we agree on what introsort means -- normally I take it to
> > mean doing an O(n²) algorithm with good "typical case" performance to
> > begin with, but switching to an O(log n) algorithm with a worse
> > constant factor as soon as it detects a risk that time will grow
> > quadratically. Normally this is something like starting with quicksort
> > and possibly switching to heapsort, and my understanding at the time
> > was that glibc was doing that or something similar, and AFAIK it still
> > is in the general case where there's insufficient memory for a merge
> > sort. Does that sound incorrect?
> >
> > Rich
>
> At least the version I was looking at (2.19) doesn't do that at all. As
> I said, even in case of failed malloc(), all it does is a quicksort.
> With an insertion sort afterwards, but that's not introsort by either of
> our definitions. And in any case, malloc() failure is rare these days,
i think malloc failure case is the one that matters
for worst case analysis so the comparision table
should say whatever quicksort is doing.
next prev parent reply other threads:[~2017-09-13 19:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-13 13:51 Markus Wichmann
2017-09-13 18:10 ` Rich Felker
2017-09-13 18:51 ` Markus Wichmann
2017-09-13 19:25 ` Szabolcs Nagy [this message]
2017-09-13 19:53 ` Rich Felker
2017-09-15 19:18 ` Markus Wichmann
2017-09-16 9:37 ` Szabolcs Nagy
2017-09-16 14:01 ` Markus Wichmann
2017-09-16 17:11 ` Szabolcs Nagy
2017-09-16 19:34 ` Markus Wichmann
2017-09-16 16:18 ` Rich Felker
2017-09-16 18:38 ` Markus Wichmann
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