From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Stezenbach Subject: linux-3.2.1 + KVM: TSC unstable on Core i5-2400S / H67 Date: Tue, 24 Jan 2012 12:36:08 +0100 Message-ID: <20120124113608.GA16876@sig21.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel@vger.kernel.org To: kvm@vger.kernel.org Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Hi, I just got the following in dmesg with linux-3.2.1: [23379.612251] usb 2-1.2: new high-speed USB device number 6 using ehci_hcd [ 0.006666] Marking TSC unstable due to KVM discovered backwards TSC [23421.511167] Switching to clocksource hpet The mainboard is an Asus P8H67-V, BIOS 0806 10/26/2011 with Core i5-2400S. The kvm instance was running for a day already, and there was an overnight suspend-to-disk cycle in between, but the above happened ~1 hour after resume. (I don't think the usb message has anything to do with it, it's just the last message before the TSC message.) Hm, checking /var/log/kern.* it seems this also happened with linux-3.1.* without me noticing. Should I be worried? I thought Core-i5 processors have a stable TSC? Johannes