Re: [Qemu-devel] kvm suspend performance

2013-03-25 Thread Eric Blake
On 03/23/2013 06:42 AM, Thomas Knauth wrote: Hi Eric, thanks for the reply. This indeed solved my issue. Suspending is much faster without the artificial throttle. On a related note: I'm curious about the baseline resume latency. It takes about 5 seconds to resume an instance with a tiny

Re: [Qemu-devel] kvm suspend performance

2013-03-23 Thread Thomas Knauth
Hi Eric, thanks for the reply. This indeed solved my issue. Suspending is much faster without the artificial throttle. On a related note: I'm curious about the baseline resume latency. It takes about 5 seconds to resume an instance with a tiny amount of state (500 MB dump size). The data is all

Re: [Qemu-devel] kvm suspend performance

2013-03-20 Thread Stefan Hajnoczi
On Tue, Mar 19, 2013 at 05:24:59PM +0100, Thomas Knauth wrote: lately I've been playing around with qemu's/kvm's suspend (to disk) and resume. My initial expectation was that both operations are I/O bound. So it surprised me to see that suspend to disk seems to be CPU-bound. Suspending a VM

Re: [Qemu-devel] kvm suspend performance

2013-03-20 Thread Thomas Knauth
Hi Stefan, thanks for taking the time to reply. On Wed, Mar 20, 2013 at 9:11 AM, Stefan Hajnoczi stefa...@gmail.com wrote: Which QEMU or libvirt command are you using to suspend the guest to disk? virsh save name file Why do you say it is CPU-bound? Did you use a tool like vmstat or

Re: [Qemu-devel] kvm suspend performance

2013-03-20 Thread Eric Blake
On 03/20/2013 04:44 PM, Thomas Knauth wrote: Hi Stefan, thanks for taking the time to reply. On Wed, Mar 20, 2013 at 9:11 AM, Stefan Hajnoczi stefa...@gmail.com wrote: Which QEMU or libvirt command are you using to suspend the guest to disk? virsh save name file Then this is as

[Qemu-devel] kvm suspend performance

2013-03-19 Thread Thomas Knauth
Dear all, lately I've been playing around with qemu's/kvm's suspend (to disk) and resume. My initial expectation was that both operations are I/O bound. So it surprised me to see that suspend to disk seems to be CPU-bound. Suspending a VM with 1.5 GB memory takes 55 seconds. This works out to