From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: qemu-kvm upstreaming: Do we want -kvm-shadow-memory semantics? Date: Wed, 25 Jan 2012 12:57:19 +0100 Message-ID: <4F1FEE1F.8080907@siemens.com> References: <4F1810AF.8010002@siemens.com> <20120119172802.GD11381@amt.cnet> <4F185535.1060908@siemens.com> <4F1FE9CE.5050401@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , qemu-devel , kvm To: Avi Kivity Return-path: In-Reply-To: <4F1FE9CE.5050401@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org List-Id: kvm.vger.kernel.org On 2012-01-25 12:38, Avi Kivity wrote: > On 01/19/2012 07:39 PM, Jan Kiszka wrote: >> On 2012-01-19 18:28, Marcelo Tosatti wrote: >>> On Thu, Jan 19, 2012 at 01:46:39PM +0100, Jan Kiszka wrote: >>>> Hi again, >>>> >>>> do we need some KVM knob comparable to qemu-kvm's -kvm-shadow-memory in >>>> upstream? >>>> >>>> If yes: The underlying IOCTL is x86-only. Are other archs interested in >>>> this long-term as well, ie. should the control become arch-independent? >>>> >>>> Jan >>> >>> Last time i asked about removal, Avi wished for it to remain. >>> >> >> Then I guess he should comment on this after returning to work. :) > > -kvm-shadow-memory is becoming less meaningful for ordinary workloads > since everything uses TDP these days. It's still meaningful for testing > (forcing aggressive cache replacement), or perhaps nested virtualization. So, is it used for testing in fact? Would a machine option "kvm_shadow_memory=n" be desirable? Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux