Re: Fast memcpy patch

From: Sasha Levin
Date: Wed Nov 23 2011 - 07:12:53 EST


On Wed, 2011-11-23 at 12:25 +0100, N. Coesel wrote:
> Dear readers,
> I noticed the Linux kernel still uses a byte-by-byte copy method for
> memcpy. Since most memory allocations are aligned to the integer size
> of a cpu it is often faster to copy by using the CPU's native word
> size. The patch below does that. The code is already at work in many
> 16 and 32 bit embedded products. It should also work for 64 bit
> platforms. So far I only tested 16 and 32 bit platforms.

[snip]

memcpy (along with other mem* functions) are arch specific - for
example, look at arch/x86/lib/memcpy_64.S for the implementation(s) for
x86.

The code under lib/string.c is simple and should work on all platforms
(and is probably not being used anywhere anymore).

--

Sasha.

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