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Re: [PATCH] Saving a few cycles, part 1/2

From: John Szakmeister <john_at_szakmeister.net>
Date: Mon, 26 Apr 2010 18:55:40 -0400

On Mon, Apr 26, 2010 at 5:23 AM, Philip Martin
<philip.martin_at_wandisco.com> wrote:
> Stefan Fuhrmann <stefanfuhrmann_at_alice-dsl.de> writes:
>
>> further reducing my backlog of patches sitting in my
>> working copy, this and the next patch optimize code
>> locally - shaving off cycles here and there. The net
>> effect is somewhere between 3 and 10 percent
>> for repository access (ls, export, etc.).
>>
>> In this patch, I eliminated calls to memcpy for small
>> copies as they are particularly expensive in the MS CRT.
>
> For gcc (on Linux at least) memcpy is automatically inlined for small
> copies.  Obscuring the memcpy could well result in worse code.

And I believe we're enabling intrinsics in the Windows build... so
it's being inlined there too. I agree, I don't like obscuring
memcpy() either.

-John
Received on 2010-04-27 01:14:09 CEST

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