On Tue, May 19, 2015 at 04:50:17PM +0800, Borislav Petkov wrote: > On Tue, May 19, 2015 at 03:25:53PM +0800, Huang Rui wrote: > > Apology that cause to misunderstand. It's not as same as intel. > > Intel is able to go to C1E like you said, the C1E has less power > > consumption than C1 on Intel platform. > > You still misunderstand - I'm not talking about Intel platforms here but > AMD ones. On AMD we never enter idle with MWAIT - we do HLT which enters > C1 and then the hw enters C1E when a bunch of conditions are fulfilled. >
OK, got it. I see on AMD platforms, we all use default_idle (HLT). > > The faster waiting exit speed. But it's hard to test the improvement, > > do you have any idea? It's told by HW designer. > > You can test the improvement with a special setup only. Unless you can > read out power consumption of a box while it is idle. > Could you please explain how to create the "special setup"? Actually, that's my difficulty. > The exit-idle speed only does not suffice to switch to MWAIT though, > IMHO. I think power consumption in idle should be the relevant metric > here. > Yes, I agree with you. So that's why I was asking to provide an optional parameter, not set it default. > > Current CPU, power consumption cannot go to deeper low power state > > (C1) via mwaitx/mwait. But HW designers will implement it in future > > processors. > > So future CPUs we will switch to MWAIT. I don't see a problem with that. > Yes, at that time, we would like to use mwaitx/mwait as default idle routine for AMD. Thanks, Rui -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
