From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754437Ab2IXLex (ORCPT ); Mon, 24 Sep 2012 07:34:53 -0400 Received: from casper.infradead.org ([85.118.1.10]:36688 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754049Ab2IXLev convert rfc822-to-8bit (ORCPT ); Mon, 24 Sep 2012 07:34:51 -0400 Message-ID: <1348486479.11847.46.camel@twins> Subject: Re: [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenarios in PLE handler From: Peter Zijlstra To: Raghavendra K T Cc: "H. Peter Anvin" , Marcelo Tosatti , Ingo Molnar , Avi Kivity , Rik van Riel , Srikar , "Nikunj A. Dadhania" , KVM , Jiannan Ouyang , chegu vinod , "Andrew M. Theurer" , LKML , Srivatsa Vaddagiri , Gleb Natapov Date: Mon, 24 Sep 2012 13:34:39 +0200 In-Reply-To: <20120921115942.27611.67488.sendpatchset@codeblue> References: <20120921115942.27611.67488.sendpatchset@codeblue> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2012-09-21 at 17:29 +0530, Raghavendra K T wrote: > In some special scenarios like #vcpu <= #pcpu, PLE handler may > prove very costly, because there is no need to iterate over vcpus > and do unsuccessful yield_to burning CPU. What's the costly thing? The vm-exit, the yield (which should be a nop if its the only task there) or something else entirely?