From mboxrd@z Thu Jan 1 00:00:00 1970 From: Preeti U Murthy Subject: Re: [PATCH] cpuidle: powernv/pseries: Decrease the snooze residency Date: Sat, 30 May 2015 13:30:23 +0530 Message-ID: <55696E17.2030700@linux.vnet.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=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from e19.ny.us.ibm.com ([129.33.205.209]:38324 "EHLO e19.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751038AbbE3IAb (ORCPT ); Sat, 30 May 2015 04:00:31 -0400 Received: from /spool/local by e19.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sat, 30 May 2015 04:00:30 -0400 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: 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 On 05/30/2015 11:31 AM, Vaidyanathan Srinivasan wrote: > * 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. > Oh Ok! Thanks for the clarification ! Regards Preeti U Murthy > --Vaidy >