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.guent...@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
