From mboxrd@z Thu Jan 1 00:00:00 1970 From: Farkas Levente Subject: Re: windows 2003 smp guest Date: Thu, 20 Sep 2007 23:36:53 +0200 Message-ID: <46F2E7F5.7080105@bppiac.hu> References: <46EFDB2C.30601@qumranet.com> <37E52D09333DE2469A03574C88DBF40FA9C23E@pdsmsx414.ccr.corp.intel.com> <46F2E17E.20607@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel , "He, Qing" , Avi Kivity To: dor.laor-atKUWr5tajBWk0Htik3J/w@public.gmane.org Return-path: In-Reply-To: <46F2E17E.20607-atKUWr5tajBWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Dor Laor wrote: > Haydn Solomon wrote: >> I have a question on guest smp performance. If I have a host with core >> 2 duo, should a kvm guest perform better using -smp 2 as opposed to >> not using -smp 2? >> > Well, it depends: > In general Avi measured 40% performance increase for using a second cpu > in the guest. This was long time ago, > before the in-kernel-apic implementation. It might improve the gain of > the additional cpu. > > On the other hand, for 32 bit windows, using ACPI HAL has pretty big > overhead at the moment. Since it is a must > for smp guest, it might be slower than running non-acpi single cpu VM. can you tell me what does the HAL means here? and what's kind of HAL exists what are the advantage/disadvantages them. how can i change/configure this? -- Levente "Si vis pacem para bellum!" ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/