From: Alexander Monakov <amonakov@ispras.ru>
To: musl@lists.openwall.com
Cc: "Érico Nogueira" <ericonr@disroot.org>
Subject: Re: [musl] [PATCH v2] add qsort_r.
Date: Tue, 9 Mar 2021 12:11:37 +0300 (MSK) [thread overview]
Message-ID: <alpine.LNX.2.20.13.2103091200160.16269@monopod.intra.ispras.ru> (raw)
In-Reply-To: <20210309035652.32453-1-ericonr@disroot.org>
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On Tue, 9 Mar 2021, Érico Nogueira wrote:
> since most discussion around the addition of this function has centered
> around the possible code duplication it requires or that qsort would
> become much slower if implemented as a wrapper around qsort_r
How much is "much slower", did anyone provide figures to support this claim?
The extra cost that a wrapper brings is either one indirect jump instruction,
or one trivially-predictable conditional branch per one comparator invocation.
Constant factor in musl qsort is quite high, I'd be surprised if the extra
overhead from one additional branch is even possible to measure.
Alexander
next prev parent reply other threads:[~2021-03-09 9:11 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-09 3:56 Érico Nogueira
2021-03-09 9:11 ` Alexander Monakov [this message]
2021-03-09 13:42 ` Rich Felker
2021-03-09 14:13 ` Alexander Monakov
2021-03-09 15:03 ` Rich Felker
2021-03-09 16:54 ` Markus Wichmann
2021-03-09 18:04 ` Rich Felker
2021-03-15 23:49 ` Alexander Monakov
2021-03-16 2:18 ` Rich Felker
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