From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenarios
 in PLE handler
Date: Mon, 24 Sep 2012 13:34:39 +0200
Message-ID: <1348486479.11847.46.camel@twins>
References: <20120921115942.27611.67488.sendpatchset@codeblue>
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Cc: "H. Peter Anvin" <hpa@zytor.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Ingo Molnar <mingo@redhat.com>, Avi Kivity <avi@redhat.com>,
	Rik van Riel <riel@redhat.com>,
	Srikar <srikar@linux.vnet.ibm.com>,
	"Nikunj A. Dadhania" <nikunj@linux.vnet.ibm.com>,
	KVM <kvm@vger.kernel.org>, Jiannan Ouyang <ouyang@cs.pitt.edu>,
	chegu vinod <chegu_vinod@hp.com>,
	"Andrew M. Theurer" <habanero@linux.vnet.ibm.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Srivatsa Vaddagiri <srivatsa.vaddagiri@gmail.com>,
	Gleb Natapov <gleb@redhat.com>
To: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <20120921115942.27611.67488.sendpatchset@codeblue>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.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?