From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [PATCH V2 Resend 0/4] Create sched_select_cpu() and use it for workqueues and timers Date: Mon, 26 Nov 2012 12:35:52 -0500 Message-ID: <1353951352.6276.43.camel@gandalf.local.home> References: <1353948027.6276.38.camel@gandalf.local.home> <20121126170358.GE2474@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: 7bit Cc: Viresh Kumar , pjt@google.com, paul.mckenney@linaro.org, tglx@linutronix.de, tj@kernel.org, suresh.b.siddha@intel.com, venki@google.com, mingo@redhat.com, peterz@infradead.org, Arvind.Chauhan@arm.com, linaro-dev@lists.linaro.org, patches@linaro.org, pdsw-power-team@arm.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org To: paulmck@linux.vnet.ibm.com Return-path: Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:12240 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933715Ab2KZRfy (ORCPT ); Mon, 26 Nov 2012 12:35:54 -0500 In-Reply-To: <20121126170358.GE2474@linux.vnet.ibm.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Mon, 2012-11-26 at 09:03 -0800, Paul E. McKenney wrote: > If I understand correctly (though also suffering turkey OD), the idea is > to offload work to more energy-efficient CPUs. This is determined by a CPU that isn't running the idle task? Is it because a CPU that just woke up may be running at a lower freq, and thus not as efficient? But pushing off to another CPU may cause cache misses as well. Wouldn't that also be a factor in efficiencies, if a CPU is stalled waiting for memory to be loaded? I should also ask the obvious. Has these patches shown real world efficiencies or is this just a theory? Do these patches actually improve battery life when applied? Just asking. -- Steve