From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerd Hoffmann Subject: Re: [PATCH 0/4] paravirt clock patches Date: Mon, 05 May 2008 09:47:59 +0200 Message-ID: <481EBBAF.8090807@redhat.com> References: <1209026228-9113-1-git-send-email-kraxel@redhat.com> <20080428192816.GA4596@dmt> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, Glauber de Oliveira Costa To: Marcelo Tosatti Return-path: In-Reply-To: <20080428192816.GA4596@dmt> 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 Marcelo Tosatti wrote: > On Thu, Apr 24, 2008 at 10:37:04AM +0200, Gerd Hoffmann wrote: >> Hi folks, >> >> My first attempt to send out a patch series with git ... >> >> The patches fix the kvm paravirt clocksource code to be compatible with >> xen and they also factor out some code which can be shared into a >> separate source files used by both kvm and xen. > > The issue with SMP guests is still present. Booting with "nohz=off" resolves it. > > Same symptoms as before, apic_timer_fn for one of the vcpu's is ticking way slower > than the remaining ones: > > [root@localhost ~]# cat /proc/timer_stats | grep apic > 391, 4125 qemu-system-x86 apic_mmio_write (apic_timer_fn) > 2103, 4126 qemu-system-x86 apic_mmio_write (apic_timer_fn) > 1896, 4127 qemu-system-x86 apic_mmio_write (apic_timer_fn) > 1857, 4128 qemu-system-x86 apic_mmio_write (apic_timer_fn) What userspace version is this? With iothread support? Or older one where the vcpu0 thread also handles all the I/O? Is 4x neeed to reproduce or do you see it with 2x too? What host? A quick test with xenner (which has a separate I/O thread) didn't show anything unusual. Going investigate ... cheers, Gerd -- http://kraxel.fedorapeople.org/xenner/ ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone