From: Joe Perches <joe@perches.com>
To: Alexey Dobriyan <adobriyan@gmail.com>, akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, Andi Kleen <andi@firstfloor.org>
Subject: Re: [PATCH] smaller strlen()
Date: Fri, 26 Aug 2016 15:23:21 -0700 [thread overview]
Message-ID: <1472250201.4914.88.camel@perches.com> (raw)
In-Reply-To: <20160826200120.GA1852@p183.telecom.by>
On Fri, 2016-08-26 at 23:01 +0300, Alexey Dobriyan wrote:
> gcc prefers "*s++" style code for some reason, doesn't unroll loop
> condition check once. Kernel strings are small but they aren't of 0
> length, so that additional branch was almost never taken.
Hey Alexey.
Is this gcc version specific?
And I'm confused why there isn't an asm __HAVE_ARCH_STRLEN
version x86_64 strlen like x86_32 or if __builtin_strlen()
is or isn't used. Maybe Andi Kleen knows/remembers (cc'd).
> $ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux
> strlen 30 26 -4
> strlcpy 71 64 -7
> strlcat 120 99 -21
>
> strlcpy() and strlcat() are collateral damage :^)
prev parent reply other threads:[~2016-08-26 22:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-26 20:01 [PATCH] smaller strlen() Alexey Dobriyan
2016-08-26 22:23 ` Joe Perches [this message]
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