From mboxrd@z Thu Jan 1 00:00:00 1970 From: Koen Vermeer Subject: Re: Clock off in guest Date: Thu, 14 Feb 2008 10:10:03 +0100 Message-ID: <1202980203.5438.8.camel@localhost> References: <21445.78.27.39.91.1202907163.squirrel@vermeer.tv> <64F9B87B6B770947A9F8391472E032160B5F84F0@ehost011-8.exch011.intermedia.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net To: Uri Lublin Return-path: In-Reply-To: <64F9B87B6B770947A9F8391472E032160B5F84F0@ehost011-8.exch011.intermedia.net> 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 On Wed, 2008-02-13 at 09:58 -0800, Uri Lublin wrote: > The host kernel or kvm. > If you choose to upgrade your host kernel (and kvm that comes with > it), make sure > you are using recent kvm-userspace too (e.g. kvm-60). Running 2.6.23 on the host with kvm 60 (userspace) and kvm-source 60 (modules). > > >> Or as an alternative, probably not as good, sometimes (when the > guest's > >> clocksource is PIT) adding '-tdf' to the command line helps. > >I cannot find this in man kvm or man qemu. > I'm not sure about the man pages, but kvm/qemu's help says: > bash$ /usr/bin/kvm -h | grep tdf > -tdf inject timer interrupts that got lost > It doesn't seem to be mentioned in the man pages, but it is indeed there when running 'kvm --help'. > Yes, try adding it to the command line that starts the guest > (executable name may vary): > /usr/bin/kvm [kvm-params] -tdf > Also tdf (time drift fix) only works when using PIT+PIC (no APIC) so > sometimes it's helpful > to also add -no-acpi: > /usr/bin/kvm [kvm-params] -tdf -no-acpi > I tried both -tdf and -tdf -no-acpi, but it didn't change anything. I did notice some lines on the host saying time drift is too long, 60 seconds were lost which weren't there when running without '-tdf'. You were saying -tdf only works when using PIT+PIC, but, as far as I can tell, the guest is still using tsc. Should I add a kernel parameter like clocksource=pit to the guest? I appreciate the help! Koen ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/