From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH 5/5] KVM: paravirt time source Date: Tue, 19 Jun 2007 16:38:36 -0500 Message-ID: <46784CDC.9070403@codemonkey.ws> References: <4675F462.1010708@codemonkey.ws> <4675F601.3090706@codemonkey.ws> <4676D8E4.3020806@goop.org> <46783EDB.5010808@codemonkey.ws> <46784A0E.3080502@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <46784A0E.3080502-TSDbQ3PG+2Y@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 To: Jeremy Fitzhardinge Cc: kvm-devel , virtualization List-Id: virtualization@lists.linuxfoundation.org Jeremy Fitzhardinge wrote: > Anthony Liguori wrote: > >> I've updated this patch and switched to using a scale/shift like Xen >> is doing, but I must admit, I don't understand how it helps adjtime. >> I poked around a bit and it wasn't obvious. >> >> Why is having {mult=1<<22, shift=22} better for adjtime than {mult=1, >> shift=0}? >> > > I don't fully understand it myself, but I think its because adjtime > plays with the mult factor to scale the rate at which time passes. If > the scale is 1, then it can only scale time by integer amounts. By > setting it to 2^22, then it can adjust time down to 1 part in 4 million. > Ah, thanks. Regards, Anthony Liguori > J > > ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/