Re: stack alignment in the kernel was Re: nasm over gas?

[Jamie Lokier]

Andi Kleen wrote:
> The stack adjustments are for getting good performance with floating
> point code. Most x86 CPUs require 16 byte alignment for floating point
> stores/loads on the stack. It can make a dramatic difference in some 
> FP intensive programs.

You're right.

> A compiler option to turn it off would make sense to save .text space
> and eliminate these useless instructions. Especially since the kernel
> entry points make no attempt to align the stack to 16 byte anyways,
> so most likely the stack adjustments do not even work.

There is an option:

	-mpreferred-stack-boundary=2

-- Jamie
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