Re: [benchmark] 1% performance overhead of paravirt_ops on nativekernels

[Linus Torvalds]

On Fri, 5 Jun 2009, Rusty Russell wrote:
> 
> Distributions don't ship UP kernels any more; this shows what that costs if 
> you're actually on a UP box.  If we really don't care, perhaps we should make 
> CONFIG_SMP=n an option under EMBEDDED for x86.  And we can rip out the complex 
> patching SMP patching stuff too.

The complex SMP patching is what makes it _possible_ to not ship UP 
kernels any more.

The SMP overhead exists, but it would be even higher if we didn't patch 
things to remove the "lock" prefix.

		Linus
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