[libvirt] [PATCH 0/8 v5] Summary on block IO throttle

[Stefan Hajnoczi]

On Wed, Nov 23, 2011 at 4:59 AM, Zhi Yong Wu <zwu.kernel at gmail.com> wrote:
> On Wed, Nov 23, 2011 at 12:27 PM, Eric Blake <eblake at redhat.com> wrote:
>> On 11/15/2011 02:02 AM, Lei Li wrote:
>>> Changes since V3
>>>  - Use virTypedParameterPtr instead of specific struct in libvirt pulic API.
>>>  - Relevant changes to remote driver, qemu driver, python support and virsh.
>>>
>>> To help add QEMU I/O throttling support to libvirt, we plan to complete
>>> it with add new API virDomain{Set, Get}BlockIoThrottle(), new command 'blkdeviotune'
>>> and Python bindings.
>>>
>>> Notes: Now all the planed features were implemented (#1#2 were implemented by
>>> Zhi Yong Wu), the previous comments were all fixed up too. And the qemu part patches
>>> have been accepted upstream and are expected to be part of the QEMU 1.1
>>> release, git tree from Zhi Yong:
>>>
>>> http://repo.or.cz/w/qemu/kevin.git/shortlog/refs/heads/block
>>
>> I just realized that the block_set_io_throttle monitor command is not
>> yet in released upstream qemu.  I will continue reviewing this series,
>> but it's harder to justify including it into libvirt 0.9.8 unless we
>> have a good feel that the design for qemu is stable and unlikely to
> I strongly think that the syntax of this qemu monitor command will be
> not changed later. :)
> Moreover, it has not been changed since the patches for qemu block I/O
> throttling is published.

It's good to be careful about adding libvirt features that are not yet
in QEMU.  I got burnt by this with image streaming and have had to
work extra hard to finally get the QEMU side merged with the libvirt
side already set in stone.

However, Kevin has merged the QEMU I/O throttling patches into the
block tree.  They are waiting for the 1.1 merge window because
qemu.git has only been taking QEMU 1.0-rc patches for the past few
weeks.  QEMU I/O throttling has been through review and accepted by
the community:

http://patchwork.ozlabs.org/patch/124266/

Stefan