From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: zengzhaoxiu@163.com, akpm@linux-foundation.org,
linux@horizon.com, peterz@infradead.org
Cc: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>,
Richard Henderson <rth@twiddle.net>,
Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Matt Turner <mattst88@gmail.com>,
Russell King <linux@arm.linux.org.uk>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Geert Uytterhoeven <geert@linux-m68k.org>,
James Hogan <james.hogan@imgtec.com>,
Michal Simek <monstr@monstr.eu>,
Ralf Baechle <ralf@linux-mips.org>,
Ley Foon Tan <lftan@altera.com>, Jonas Bonn <jonas@southpole.se>,
"James E.J. Bottomley" <jejb@parisc-linux.org>,
Helge Deller <deller@gmx.de>, Chen Liqin <liqin.linux@gmail.com>,
Lennox Wu <lennox.wu@gmail.com>, Rich Felker <dalias@libc.org>,
"David S. Miller" <davem@davemloft.net>,
linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
uclinux-h8-devel@lists.sourceforge.jp,
linux-m68k@lists.linux-m68k.org, linux-metag@vger.kernel.org,
linu
Subject: Re: [patch V3] lib: GCD: add binary GCD algorithm
Date: Thu, 28 Apr 2016 10:22:50 -0700 [thread overview]
Message-ID: <1461864170.2307.19.camel@HansenPartnership.com> (raw)
In-Reply-To: <1461843824-19853-1-git-send-email-zengzhaoxiu@163.com>
On Thu, 2016-04-28 at 19:43 +0800, zengzhaoxiu@163.com wrote:
> From: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
>
> Because some architectures (alpha, armv6, etc.) don't provide
> hardware division, the mod operation is slow! Binary GCD algorithm
> uses simple arithmetic operations, it replaces division with
> arithmetic shifts, comparisons, and subtractions.
>
> I have compiled successfully with x86_64_defconfig and
> i386_defconfig.
What's the reason for wanting to optimize this and thus have to
maintain (and test) two separate code paths, which is a significant
expense? As far as I can see, gcd() is mosly used in finding optimal
clocks for operations, which is usually done at start of day and not
time critical.
James
prev parent reply other threads:[~2016-04-28 17:22 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-28 11:43 [patch V3] lib: GCD: add binary GCD algorithm zengzhaoxiu
2016-04-28 12:18 ` kbuild test robot
2016-04-28 16:48 ` George Spelvin
2016-04-28 17:51 ` Geert Uytterhoeven
2016-04-28 17:58 ` Rich Felker
2016-04-28 18:11 ` Geert Uytterhoeven
2016-04-28 19:15 ` George Spelvin
[not found] ` <20160428164856.10120.qmail-HzZAx2gCgqrSUeElwK9/Pw@public.gmane.org>
2016-04-28 19:54 ` Sam Ravnborg
[not found] ` <1461843824-19853-1-git-send-email-zengzhaoxiu-9Onoh4P/yGk@public.gmane.org>
2016-04-28 17:10 ` Josh Juran
2016-05-20 10:27 ` kbuild test robot
2016-04-28 17:22 ` James Bottomley [this message]
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