Re: [PATCH v2 3/4] x86, mwaitt: introduce mwaix delay with a configurable timer

[Huang Rui <ray.huang@amd.com>]

On Tue, Jun 09, 2015 at 04:31:03PM +0800, Peter Zijlstra wrote:
> On Tue, Jun 09, 2015 at 11:13:40AM +0800, Huang Rui wrote:
> > MWAITX can enable a timer and a corresponding timer value specified in SW
> > P0 clocks. The SW P0 frequency is the same with TSC. The timer provides an
> > upper bound on how long the instruction waits before exiting.
> > 
> > The implementation of delay function in kernel can lerverage the timer of
> > MWAITX. This patch provides a new method (delay_mwaitx) to measure delay
> > time.
> 
> But does this actually default to mwaitx delay on capable hardware? If
> you need to boot with that parameter it means nobody is ever going to
> use this.

Oh, I see. Actually, you're right. Maybe nobody except us will use it.
Will update in V3.

Thanks,
Rui