Re: [CFS Bandwidth Control v4 0/7] Introduction

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

On Mon, Feb 21, 2011 at 10:47:12AM +0800, Xiao Guangrong wrote:
> On 02/16/2011 11:18 AM, Paul Turner wrote:
> > Hi all,
> > 
> > Please find attached v4 of CFS bandwidth control; while this rebase against
> > some of the latest SCHED_NORMAL code is new, the features and methodology are
> > fairly mature at this point and have proved both effective and stable for
> > several workloads.
> > 
> > As always, all comments/feedback welcome.
> > 
> 
> Hi Paul,
> 
> Thanks for the great features!
> 
> I applied the patchset to kvm tree, then tested with kvm guest, unfortunately,
> it seems don't work normally. 
> 
> The steps is follow:
> 
> # mount -t cgroup -o cpu none /mnt/
> # qemu-system-x86_64 -enable-kvm  -smp 4 -m 512M -drive file=fc64.img,index=0,media=disk
> 
> Don't do any configuration in cgroup, and run the kvm guest directly (don't use libvirt),
> the guest booted very slowly and i saw some "soft lockup" bugs reported in the guest,
> i also noticed one CPU usage is 100% for more than 60s and other CPUs is 10%~30% in the host
> when guest was booting.
> 
> And if cgroup is not mounted, the guest runs well.
> 

Hi Xiao Guangrong,

Thanks for testing the patches. I do see some soft lockups in the
guest when I mount the cgroup and start VM using qemu-kvm.

Will get back after further investigation.

Regards,
Bharata.