Re: [PATCH v2 1/4] x86, mwaitt: add monitorx and mwaitx instruction

From: Peter Zijlstra
Date: Tue Jun 09 2015 - 04:23:41 EST


On Tue, Jun 09, 2015 at 11:13:38AM +0800, Huang Rui wrote:
>
> MWAITX ECX[1]: enable timer if set
> MWAITX EBX[31:0]: max wait time expressed in SW P0 clocks
>
> The software P0 frequency is the same as the TSC frequency.
>
> Max timeout = EBX/(TSC frequency)

^ that, would make a lovely comment for this v

> +static inline void __mwaitx(unsigned long eax, unsigned long ebx,
> + unsigned long ecx)
> +{
> + /* "mwaitx %eax, %ebx, %ecx;" */
> + asm volatile(".byte 0x0f, 0x01, 0xfb;"
> + :: "a" (eax), "b" (ebx), "c" (ecx));
> +}
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