lkml.org 
[lkml]   [2015]   [Apr]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] Use -mskip-rax-setup if supported
On Thu, Apr 16, 2015 at 02:23:44PM -0700, H.J. Lu wrote:
> GCC 5 added a compiler option, -mskip-rax-setup, for x86-64. It skips
> setting up the RAX register when SSE is disabled and there are no
> variable arguments passed in vector registers. Since kernel doesn't
> pass vector registers to functions with variable arguments, this option
> can be used to optimize the x86-64 kernel. For kernel 3.17:
>
> text data bss dec hex filename
> 11455921 2204048 5853184 19513153 129bf41 vmlinux #with -mskip-rax-setup
> 11480079 2204048 5853184 19537311 12a1d9f vmlinux
>
>
> --
> H.J.

> From a759c1a4f6ffa408d49e1959449d6797769b951e Mon Sep 17 00:00:00 2001
> From: "H.J. Lu" <hjl.tools@gmail.com>
> Date: Wed, 17 Dec 2014 18:05:29 -0800
> Subject: [PATCH] Use -mskip-rax-setup if supported
>
> GCC 5 added a compiler option, -mskip-rax-setup, for x86-64. It skips
> setting up the RAX register when SSE is disabled and there are no
> variable arguments passed in vector registers. Since kernel doesn't
> pass vector registers to functions with variable arguments, this option
> can be used to optimize the x86-64 kernel. For kernel 3.17:
>
> text data bss dec hex filename
> 11455921 2204048 5853184 19513153 129bf41 vmlinux #with -mskip-rax-setup
> 11480079 2204048 5853184 19537311 12a1d9f vmlinux
>
> Signed-off-by: H.J. Lu <hjl.tools@gmail.com>

Applied, thanks.

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
--


\
 
 \ /
  Last update: 2015-04-25 19:41    [W:0.043 / U:0.160 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site