Re: Efficient x86 and x86_64 NOP microbenchmarks

[Linus Torvalds]

On Wed, 13 Aug 2008, Andi Kleen wrote:
> 
> Also I must say the whole ftrace noping exercise is pretty pointless without
> avoiding frame pointers because it does save less than what you lose
> unconditionally from the "select FRAME_POINTER"

Andi, you seem to have missed the whole point. This is a _correctness_ 
issue as long as the nop is not a single instruction. And the workaround 
for that is uglier than just making a single-instruction nop.

So the question now is to find a good nop that _is_ a single atomic 
instruction. Your blathering about frame pointers is missing the whole 
point!

			Linus
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