PATCH: Add pause intrinsic

[Paul Koning]

On May 26, 2011, at 1:37 PM, Andi Kleen wrote:

> On Thu, May 26, 2011 at 06:46:39PM +0200, Jakub Jelinek wrote:
>> On Thu, May 26, 2011 at 09:10:32AM -0700, Andi Kleen wrote:
>>> Richard Guenther <richard.guenther@gmail.com> writes:
>>> As for why having a builtin: one reason would be portability.
>> 
>> You mean portability to other compilers (I think reasonable amount
>> of them support gcc-ish inline asm), or to other architectures?
> 
> Both.
> 
>> __builtin_ia32_pause () doesn't look like a builtin you would
>> want to use on PPC.
> 
> That's true, it should probably have a different name.
> 
> __builtin_pause()? 
> 
> The Linux kernel calls it cpu_relax() on all architectures.
> The following architectures implement it: ia64, powerpc, x86
> On others it just acts like a barrier.

Relax?  Weird.  "Pause" is just as weird.  It might be an ia32 instruction, so as an ia32 builtin it is a reasonable name  But if you want a generic builtin, you need a name that actually has some plausible connection with what it does, and neither "pause" nor "relax" do that.

	paul