From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikola Ciprich Subject: Re: performance tuning, problem with paravirtualized clock Date: Sun, 06 Apr 2008 23:57:02 +0200 Message-ID: <47F9472E.50602@linuxbox.cz> References: <47F934BD.7000502@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kvm-devel@lists.sourceforge.net Return-path: In-Reply-To: <47F934BD.7000502@codemonkey.ws> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Hi Anthony! Anthony Liguori wrote: > I would think you should get about 70% of native with what you've done > about. I've not seen instabilities with CONFIG_KVM_CLOCK myself. > > Setting up a hugetlbfs mount and using -mem-path may give you a bit of > a bump too but I'd be surprised if it was more than 5% I've tried it now, and starting kvm with -mem-path pointing to hugetlbfs mounted dir immediately fails and I see following message in dmesg of host: VM: killing process qemu-system-x86 pointing to tmpfs mounted dir seems to work, I'll measure performance gain... > > The next biggest win you're going to see is using NPT (available in > the recent AMD Barcelona/Phenom processors). NPT + hugetblfs should > get you pretty close to native (I'd reckon 95-98%). Yup, it seemed to me that kvm performes WAY better on my phenom based home desktop! I'll check that later too > > On the Intel side of things, you'll have to wait until the Nehalem > which will support EPT (which is Intel's version of NPT). > > Can you be specific about your guest configurations? Are you using > -smp 8? yes, I'm using -smp 8 > > Regards, > > Anthony Liguori ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Register now and save $200. Hurry, offer ends at 11:59 p.m., Monday, April 7! Use priority code J8TLD2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone