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SubjectRe: [RFC 00/17] Pile o' entry stack changes
On Wed, Sep 6, 2017 at 3:16 PM, Andi Kleen <andi@firstfloor.org> wrote:
> Andy Lutomirski <luto@kernel.org> writes:
>>
>> - Lots of people (Linus included) have asked to convert the entry
>> code to pop registers on exit instead of movqing them off the
>> stack. This makes a bunch of progress in that direction.
>
> You should benchmark it on Atoms. Likely it's a regression there
> because they don't have the special PUSH/POP acceleration.

I'm not entirely sure this is a worthwhile reason. Atom will lose a
few cycles due to POP throughput, but there's a lot less decode
bandwidth needed and we save a cache line or two.

--Andy

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