Re: [rfc patch] i386: don't save eflags on task switch

[Andi Kleen]

> sti is expensive as well; iirc just as expensive on most processors as 
> popf, 


On K8 STI is 4 cycles.

> although I don't have hard numbers to back this up on hand.  An  
> _unlikely_ jcc + popf? is better than a sti, for sure, but a likely 
> jcc+popf could cost more than a jcc+sti, depending on model.

99.9999% of all restore_flags just need STI.


-Andi
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