From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Schmitt Subject: Soft lockups and cpu frequency scaling Date: Tue, 22 Dec 2009 14:16:49 +0100 Message-ID: <4B30C6C1.9080508@scsy.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org Return-path: Received: from vmx1.f00.net ([80.242.134.136]:46602 "EHLO vmx1.f00.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750801AbZLVNZF (ORCPT ); Tue, 22 Dec 2009 08:25:05 -0500 Received: from localhost (localhost [127.0.0.1]) by vmx1.f00.net (Postfix) with ESMTP id F2EDD59747 for ; Tue, 22 Dec 2009 14:17:32 +0100 (CET) Received: from vmx1.f00.net ([127.0.0.1]) by localhost (vmx1.f00.net [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id TRpdvv+UDhuS for ; Tue, 22 Dec 2009 14:17:32 +0100 (CET) Received: from office-relay.scsy.de (p54AE5185.dip.t-dialin.net [84.174.81.133]) by vmx1.f00.net (Postfix) with ESMTPS for ; Tue, 22 Dec 2009 14:17:32 +0100 (CET) Sender: kvm-owner@vger.kernel.org List-ID: All, I'm running a manually compiled KVM on CentOS 5.4. The KVM installation has been carried over from CentOS 5.3, when KVM wasn't distributed with the OS. (I tried to migrate to CentOS 5.4 native KVM support, but wasn't able to get along with RedHat's interpretation of KVM.) The KVM version used is 88, on Kernel 2.6.18-128.7.1.el5, as KVM doesn't seem to compile on CentOS' current 2.6.18-164.9.1.el5. Only on CentOS guests, I see very frequent "soft lockup" messages and excessively hanging KVM instances. Long-term stability is fine (several months uptime), but disturbed by the hangs. The problem already was there on CentOS 5.3 as well. With the Debian guests on the same host, I have never had any apparent problems. A number of google results suggest that I should work with CPU scaling on the CentOS guest systems, but unfortunately, CPU scaling is not available in my guests. So, here's my question: How do I enable CPU scaling in KVM guests? Or is there any other measure against these soft lockups that you can recommend? Thanks everyone, -martin -- Martin Schmitt / Schmitt Systemberatung / www.scsy.de --> http://www.pug.org/index.php/Benutzer:Martin <--