[libvirt] How about realize domainSetBlockIoTune by cgroup?

[hzguanqiang at corp.netease.com]

On 2013-08-28 09:35 , Eric Blake wrote:
On 08/26/2013 10:10 PM, hzguanqiang at corp.netease.com wrote:
> Hello experts,

[please configure your mailer to wrap long lines]

> 
> It seems that blkiotune of kvm domain is set through qemu now, and We found there are some throttle shaking problem when using this interface.
> 
> As you can do the same thing through blkio cgroup, and this sounds to show better performance, Can we realize domainSetBlockIoTune by cgroup just like interface domainSetBlkioParameters ? Or Add a new interface to support setting disk IOtune by blkio cgroup?

Current libvirt already lets you choose between cgroup blkio vs. qemu io
throttling.  Compare:

http://libvirt.org/formatdomain.html#elementsBlockTuning describes
<blkiotune> (implemented via cgroups, on a per-host-block-device basis);
mapped through the virDomainSetBlkioParameters API, or via 'virsh blkiotune'

http://libvirt.org/formatdomain.html#elementsDisks describes <iotune>
under <disk> (implemented via qemu, on a per-guest-disk basis); mapped
through the virDomainSetBlockIoTune API, or via 'virsh blkdeviotune'

(and yes, we're lousy at using consistently named API)

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org




Well , Eric, Thanks for your answer.  The virDomainSetBlkioParameters  API you said is just to
set the blkio.device_weight, not throttle.iops or throttle.bps just as the virDomainSetBlockIoTune
 API did.

Thanks
------------------     
Best regards!
GuanQiang
09:40:56
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