From mboxrd@z Thu Jan 1 00:00:00 1970 From: "SourceForge.net" Subject: [ kvm-Bugs-2235570 ] 100% cpu usage with KVM-78 Date: Fri, 07 Nov 2008 17:58:41 +0000 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" To: noreply@sourceforge.net Return-path: Received: from ch3.sourceforge.net ([216.34.181.60]:44457 "EHLO ch3.sourceforge.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752340AbYKGR6p (ORCPT ); Fri, 7 Nov 2008 12:58:45 -0500 Sender: kvm-owner@vger.kernel.org List-ID: Bugs item #2235570, was opened at 2008-11-07 17:58 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=893831&aid=2235570&group_id=180599 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: None Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: James Bailey (dgym) Assigned to: Nobody/Anonymous (nobody) Summary: 100% cpu usage with KVM-78 Initial Comment: When I start a guest it consumes 100% CPU on the host, even after it has booted and is sitting idle at a login prompt. The odd thing is that if I then live migrate the guest to another (identical) machine, the problem goes away. The guest continues to run just fine on the new host, and the new host's CPU usage is normal. I have tried the obvious: starting on the other machine and migrating to the first, and even multiple migrations. It is always the same, the qemu-system-x86_64 process sits at 100% unless it was started with -incoming ... Migrating machines every time you start up is not a very convenient work around, so it would be nice to find out what is different between the normal start up and the -incoming start up and fix the former. Versions and settings: KVM: 78 Host Kernel: Vanilla 2.6.25.2 Compiled with: gcc version 4.1.2 CPU: AMD Phenom Guest OS: Linux (have tried a few distros) Guest Kernels: Debian etch, and an OpenVZ 2.6.18 Command line: qemu-system-x86_64 -m 128 -smp 1 -drive file=/dev/drbd0 -vnc :1 Things I have tried which have not worked: Using -nographics. Using SDL graphics. Using -snapshot, and doing a savevm and loadvm. Things I have tried which have worked: Using -no-kvm. I have attached gdb and found the busy thread, here is its backtrace: #0 0x00007f06f017ea17 in ioctl () from /lib/libc.so.6 #1 0x000000000051b423 in kvm_run (kvm=0xa93040, vcpu=0) at libkvm.c:892 #2 0x00000000004f1116 in kvm_cpu_exec (env=) at /opt/setup/kvm-78/qemu/qemu-kvm.c:230 #3 0x00000000004f13e4 in ap_main_loop (_env=) at /opt/setup/kvm-78/qemu/qemu-kvm.c:432 #4 0x00007f06f0565135 in start_thread () from /lib/libpthread.so.0 #5 0x00007f06f01852ce in clone () from /lib/libc.so.6 #6 0x0000000000000000 in ?? () Because this indicates business within the kernel module it is as far as I have got. I will attempt to identify the previous working version, I know I never had this problem with 68, but I haven't yet tried anything in between. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=893831&aid=2235570&group_id=180599