Re: x86 memcpy performance

From: H. Peter Anvin
Date: Mon Aug 15 2011 - 14:28:16 EST

On 08/15/2011 09:58 AM, Andrew Lutomirski wrote:
> On Mon, Aug 15, 2011 at 12:12 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>> On 08/15/2011 08:36 AM, Andrew Lutomirski wrote:
>>> (*) kernel_fpu_begin is a bad name. It's only safe to use integer
>>> instructions inside a kernel_fpu_begin section because MXCSR (and the
>>> 387 equivalent) could contain garbage.
>> Uh... no, it just means you have to initialize the settings. It's a
>> perfectly good name, it's called kernel_fpu_begin, not kernel_fp_begin.
> I prefer get_xstate / put_xstate, but this could rapidly devolve into
> bikeshedding. :)

a) Quite.

b) xstate is not architecture-neutral.


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