On 10/27/2011 11:45 PM, Eric Blake wrote:
On 10/27/2011 03:12 AM, Lei Li wrote:
1) Enable the blkio throttling in xml when guest is starting up.
Add blkio throttling in xml as follows:
<disk type='file' device='disk'> <driver name='qemu' type='raw'/> <source file='/var/lib/libvirt/images/kvm-one.img'/> <target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> <iotune bps='n'.../> </disk>
2) Enable blkio throttling setting at guest running time.
virsh blkiothrottle<domain> <device> [--bps<number>] [--bps_rd<number>] \ [--bps_wr<number>] [--iops<number>] [--iops_rd<number>] [--iops_wr<number>]
3) The support to get the current block i/o throttling for a device - HMP/QMP.
virsh blkiothrottle<domain> <device>
Given that the XML is named <iotune> under <disk>, we should probably name the virsh command 'blkiotune' or 'disk-iotune', not 'blkiothrottle'.
Hi Eric, we used<iothrottle> first, I changed it since Daniel P. Berrange proposed<iotune> for per-disk element instead of<iothrottle> when we discussed at RFC V1. The command 'blkiotune' already exist, supported the cgroups blkio-controller, which handles proportional shares and throughput/iops limits on host block devices, global to the domain, but blkio throttling is specified per-disk and can vary across multiple disks. They are different two mechanism. So how about use<iothrottle> again? :)
Also, <iotune bps='n'.../> doesn't look right. This should be similar to the top-level XML. Here, taking into account the other proposal for per-block-device values (which can't be tied to individual <disk>):
<domain...> <blkiotune> <weight>800</weight> <device> <path>/path/to/device</path> <weight>200</weight> </device> </blkiotune> <devices> <disk ...> <iotune> <bps>800</bps> ... </iotune> </disk> </devices> </domain>
OK. I will do it at v3.
daemon/remote.c | 85 +++++++++++++++++ include/libvirt/libvirt.h.in | 25 +++++
Missing changes in docs/formatdomain.html.in (to describe the new XML), docs/schemas/domaincommon.rng (to validate the new xml), and tests/ (probably qemuxml2argvdata), to test it.
-- Lei