Re: PATCH] Use -mpreferred-stack-boundary=3 on x86-64 if supported

H. Peter Anvin
2012-06-23T16:17:24Z

To keep gcc from paddong the stack to maintain a nonexistent alignment.

Andi Kleen <andi@firstfloor.org> wrote:

>> This patch uses -mpreferred-stack-boundary=3 on x86-64 if it is
>supported.
>> I have been running 3.4 kernel compiled with this option for weeks.
>
>But why?
>
>All the SSE code in the kernel should adjust manually. And the other
>code doesn't need it.
>
>Besides the entry points do not guarantee alignment.
>
>For the kernel it would be probably more useful to have a attribute
>per function that forces alignment.
>
>-Andi
>--
>ak@linux.intel.com -- Speaking for myself only.

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