From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH] cpuidle: powernv/pseries: Decrease the snooze residency Date: Sat, 30 May 2015 20:38:22 -0500 Message-ID: <1433036302.4526.15.camel@au1.ibm.com> References: <1432902728-31476-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> <55686DE5.6010001@linux.vnet.ibm.com> <20150530060141.GA19134@dirshya.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from e23smtp09.au.ibm.com ([202.81.31.142]:57355 "EHLO e23smtp09.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758072AbbEaBji (ORCPT ); Sat, 30 May 2015 21:39:38 -0400 Received: from /spool/local by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sun, 31 May 2015 11:39:36 +1000 In-Reply-To: <20150530060141.GA19134@dirshya.in.ibm.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: svaidy@linux.vnet.ibm.com Cc: Preeti U Murthy , linux-pm@vger.kernel.org, Daniel Lezcano , rjw@rjwysocki.net, linux-kernel@vger.kernel.org, anton@samba.org, Shilpasri G Bhat , linuxppc-dev@lists.ozlabs.org On Sat, 2015-05-30 at 11:31 +0530, Vaidyanathan Srinivasan wrote: > In shared lpar case, spinning in guest context may potentially take > away cycles from other lpars waiting to run on the same physical cpu. > > So the policy in shared lpar case is to let PowerVM hypervisor know > immediately that the guest cpu is idle which will allow the hypervisor > to use the cycles for other tasks/lpars. But that will have negative side effects under KVM no ? Suresh mentioned something with his new directed interrupts code that we had many cases where the interrupts ended up arriving shortly after we exited to host for NAP'ing ... Snooze might fix it... Ben.