From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ch1outboundpool.messaging.microsoft.com (ch1ehsobe003.messaging.microsoft.com [216.32.181.183]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "Microsoft Secure Server Authority" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 04B022C0292 for ; Sat, 2 Feb 2013 05:15:31 +1100 (EST) Date: Fri, 1 Feb 2013 12:15:17 -0600 From: Scott Wood Subject: Re: Why is the e500v2 core not using cpuidle? To: Thomas Waldecker In-Reply-To: (from Thomas.Waldecker@tqs.de on Fri Feb 1 06:06:05 2013) Message-ID: <1359742517.23561.2@snotra> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; delsp=Yes; format=Flowed Cc: "Linux PPC dev mailing list \(linuxppc-dev@lists.ozlabs.org\)" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 02/01/2013 06:06:05 AM, Thomas Waldecker wrote: > Hi, >=20 > As part of my masterthesis I was just looking around the kernel > sources for cpuidle and figured out that the only CPU in the PowerPC > architecture using the cpuidle framework is the pseries. >=20 > I assume the e500v2 core is using the idle modes > in arch/powerpc/kernel/idle_e500.S >=20 > Why is there no support for the cpuidle framework? Because nobody implemented it. :-) The only reason I can think of to implement it on this chip would be to =20 dynamically choose when to enter nap versus doze, rather than always =20 just using doze. It's not clear whether the difference in power =20 savings is worth it -- do you have any way of measuring? > How can I debug the e500 idle modes? > Are there any statistics? Top reports idle percentage... > I already ran PowerTOP on a QorIQ P2020 but it's almost useless > because the information is missing. What information are you looking for? -Scott=