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. I suppose most CPUs that implement SMT will have some equivalent. -Andi -- a...@linux.intel.com -- Speaking for myself only.
