From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Kent Subject: linux verify_pmtmr_rate() issue Date: Tue, 21 Aug 2007 16:30:32 -0700 Message-ID: <1187739032.2562.85.camel@fuego> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: qemu-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org Return-path: 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 Issue here that's beyond my skill set to resolve: I've been starting multiple linux 2.6.23-rc3 x86 guests up in parallel with qemu/kvm and noticed pm-timer is being disabled in some of them with PM-Timer running at invalid rate: 126% of normal - aborting. in dmesg when I start about 6 at a time. Unfortunately without the timer a tickless kernel in my guests is disabled. I also replicated the issue by starting a single vm when the host system was busy enough. After some amateurish debugging added to verify_pmtmr_rate() in the kernel acpi_pm driver and get_pmtmr() in qemu acpi I can indeed see it returning just slowly enough to throw off the sanity check. [ 10.264772] DEBUG: PM-Timer running value1: 2925874 value2: 3058371 expected_rate: 107385 delta: 132497 count: 2269 [ 10.270766] PM-Timer running at invalid rate: 123% of normal - aborting. For now I've just disabled verify_pmtmr_rate() in the kernel for my guests and they seem to be keeping time just fine. Not sure if a patch for the linux kernel making the sanity check optional with a kernel parameter would make sense or there's something else that can be done at the qemu level. Thanks. -- Matthew Kent http://magoazul.com ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/