From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757549AbbE3GEF (ORCPT ); Sat, 30 May 2015 02:04:05 -0400 Received: from e23smtp09.au.ibm.com ([202.81.31.142]:47271 "EHLO e23smtp09.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753026AbbE3GD5 (ORCPT ); Sat, 30 May 2015 02:03:57 -0400 Date: Sat, 30 May 2015 11:31:41 +0530 From: Vaidyanathan Srinivasan To: Preeti U Murthy Cc: Shilpasri G Bhat , linuxppc-dev@lists.ozlabs.org, Daniel Lezcano , rjw@rjwysocki.net, linux-kernel@vger.kernel.org, anton@samba.org, linux-pm@vger.kernel.org Subject: Re: [PATCH] cpuidle: powernv/pseries: Decrease the snooze residency Message-ID: <20150530060141.GA19134@dirshya.in.ibm.com> Reply-To: svaidy@linux.vnet.ibm.com References: <1432902728-31476-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> <55686DE5.6010001@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <55686DE5.6010001@linux.vnet.ibm.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15053006-0033-0000-0000-000001950FD9 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Preeti U Murthy [2015-05-29 19:17:17]: [snip] > > + if (max_idle_state > 1) { > > + snooze_timeout_en = true; > > + snooze_timeout = cpuidle_state_table[1].target_residency * > > + tb_ticks_per_usec; > > + } > > Any idea why we don't have snooze defined on the shared lpar configuration ? 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. --Vaidy