Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933091AbbHZJM6 (ORCPT ); Wed, 26 Aug 2015 05:12:58 -0400 Received: from blu004-omc1s14.hotmail.com ([65.55.116.25]:51217 "EHLO BLU004-OMC1S14.hotmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932963AbbHZJMy (ORCPT ); Wed, 26 Aug 2015 05:12:54 -0400 X-TMN: [M+g+WLWKsFehLuNfpOFzEtwSNyjxteF5] X-Originating-Email: [wanpeng.li@hotmail.com] Message-ID: From: Wanpeng Li Subject: Re: [PATCH v2 2/3] KVM: dynamic halt_poll_ns adjustment To: David Matlack References: <1440484519-2709-1-git-send-email-wanpeng.li@hotmail.com> CC: Paolo Bonzini , kvm list , "linux-kernel@vger.kernel.org" Date: Wed, 26 Aug 2015 17:12:48 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 26 Aug 2015 09:12:52.0728 (UTC) FILETIME=[631CD780:01D0DFDF] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 951 Lines: 22 On 8/26/15 1:19 AM, David Matlack wrote: > Thanks for writing v2, Wanpeng. > > On Mon, Aug 24, 2015 at 11:35 PM, Wanpeng Li wrote: >> There is a downside of halt_poll_ns since poll is still happen for idle >> VCPU which can waste cpu usage. This patch adds the ability to adjust >> halt_poll_ns dynamically. > What testing have you done with these patches? Do you know if this removes > the overhead of polling in idle VCPUs? Do we lose any of the performance > from always polling? There is 0.8% kernel compile performance improvement(10 iterations) on host w/ 800 idle vCPUs. Btw, I handle all your comments in v3. Many thanks for your review, David! :-) Regards, Wanpeng Li -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/