From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [PATCH 2/3] cpuidle: Add a debugfs entry to disable specific C state for debug purpose. Date: Mon, 12 Mar 2012 20:46:30 +0000 Message-ID: <20120312204629.GA22929@srcf.ucam.org> References: <20120305101827.GA19408@khazad-dum.debian.net> <1330998885.1916.89.camel@ymzhang> <20120306052236.GA19416@kroah.com> <1331013078.1916.103.camel@ymzhang> <20120306143935.GA23346@kroah.com> <1331082051.1916.124.camel@ymzhang> <20120308180106.GD26516@kroah.com> <4F5DBFA8.3080300@intel.com> <4F5DC01D.7040006@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <4F5DC01D.7040006@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: ShuoX Liu Cc: "Brown, Len" , Yanmin Zhang , Greg KH , Ingo Molnar , "linux-kernel@vger.kernel.org" , Henrique de Moraes Holschuh , "H. Peter Anvin" , "Kleen, Andi" , Thomas Gleixner , "linux-pm@lists.linux-foundation.org" , Andrew Morton List-Id: linux-pm@vger.kernel.org On Mon, Mar 12, 2012 at 05:21:33PM +0800, ShuoX Liu wrote: > In addition, C state might have much impact on performance tuning, > as it takes > much time to enter/exit C states, which might delay interrupt > processing. With > the new debug option, developers could check if a deep C state could impact > performance and how much impact it could cause. Would anyone doing performance tuning not be using the cpu_dma_latency interface? -- Matthew Garrett | mjg59@srcf.ucam.org