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

On 11/23/2011 02:18 AM, Stefan Hajnoczi wrote: >>>> 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/ How can libvirt reliably tell whether block throttling is supported? Does that patch series alter the help output of 'qemu -h' to list something like '-drive ...[,bps=...]'? Is there a magic 'qemu -driver xxx,?' call where we can see that the new bps attribute is settable?