linux-kernel - Re: Mwait usage on AMD processors

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Message-ID: <20150514112303.GC29125@pd.tnic>
Date:	Thu, 14 May 2015 13:23:03 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Huang Rui <ray.huang@....com>
Cc:	Len Brown <lenb@...nel.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	linux-kernel@...r.kernel.org,
	Fengguang Wu <fengguang.wu@...el.com>,
	Aaron Lu <aaron.lu@...el.com>, Tony Li <tony.li@....com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: Mwait usage on AMD processors

On Thu, May 14, 2015 at 06:17:28PM +0800, Huang Rui wrote:
> At current processors, MWAITX cannot go to C1 state, but has faster
> waiting exit speed. MWAITX is still at C0 but less power consumption.
> So for now, I just want to set it optionally.
> HW designer will do deeper low power state (C1, and more) in future
> processors. At that time, we can enable it by default.

The only thing that matters IMO is which brings more power savings. If
C1E is still better, we should keep it the default. We can still use
MWAITX if someone boots with idle=mwait, as you say.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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