From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: KVM power usage - high wakeup rates Date: Sun, 22 Jun 2008 09:53:21 +0300 Message-ID: <485DF6E1.4060507@qumranet.com> References: <485AA6A7.2060806@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Haydn Solomon , kvm@vger.kernel.org To: Anthony Liguori Return-path: Received: from il.qumranet.com ([212.179.150.194]:32345 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750895AbYFVGxJ (ORCPT ); Sun, 22 Jun 2008 02:53:09 -0400 In-Reply-To: <485AA6A7.2060806@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: Anthony Liguori wrote: > > With the default options, my idle winxp guest causes about 550 > wakeups/sec which is pretty close to what I'd expect. I don't think > you'll get much better than that without using a dynticks guest. We keep various timers firing even if the irq lines they are tied into are masked. This generates extra interrupts, and in the case of busy guests, extra exits (though the cost is relatively low in that case). -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.