Re: P6 NOPs again: MPSC?

From: H. Peter Anvin
Date: Tue Mar 11 2008 - 02:54:01 EST


Hugh Dickins wrote:

Yup, I realized that (with || in place of &&): I meant that perhaps
it was supposed to say X86_64 || (!X86_GENERIC && (M686 || ....))
since quite a lot of other options there have "|| X86_64" to cover
all the 64-bit possibilities at once i.e. is it only MPSC that
needs to be added, or both MPSC and CPU_GENERIC?


No. The left-hand clause (X86_64 || !X86_GENERIC) indicates when using these NOPs are *permitted*; the right-hand clause indicates when doing so is *desirable*. The latter isn't, for example, for K8, even on 64 bits.

-hpa

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/