[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] blockdev-add I/O throttling parameters
From: |
Alberto Garcia |
Subject: |
Re: [Qemu-devel] blockdev-add I/O throttling parameters |
Date: |
Mon, 20 Feb 2017 17:29:19 +0100 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Mon, Feb 20, 2017 at 04:45:54PM +0100, Kevin Wolf wrote:
> > I can imagine two solutions that do not need these parameters in
> > blockdev-add:
> >
> > 1. I/O throttling is implemented by a BlockDriver. Users are expected
> > to create the BDS themselves. This is a little awkward since
> > query-block *does* include the throttling parameters in its output
> > and we must preserve this behavior for existing users.
> >
> > 2. block_set_io_throttle must be used after blockdev-add. Suboptimal
> > because issuing two commands is not atomic (use transaction?).
>
> The existing I/O throttling code is working on BlockBackends, but
> blockdev-add creates BlockDriverStates. So it can't possibly add
> throttling parameters.
>
> The currently recommended solution block_set_io_throttle. The
> other option to control BB level thorttling would be to add qdev
> properties to the block devices.
>
> In the long term, I think going with 1. and moving throttling to the
> block node level is the much nicer (and more flexible) option.
Yeah I agree with Kevin.
Berto