Messages in this thread | | | Date | Tue, 19 Jun 2012 10:21:34 +0800 | From | Asias He <> | Subject | Re: [PATCH 3/3] virtio-blk: Add bio-based IO path for virtio-blk |
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On 06/18/2012 06:13 PM, Michael S. Tsirkin wrote: > On Mon, Jun 18, 2012 at 04:03:23PM +0800, Asias He wrote: >> On 06/18/2012 03:46 PM, Rusty Russell wrote: >>> On Mon, 18 Jun 2012 14:53:10 +0800, Asias He <asias@redhat.com> wrote: >>>> This patch introduces bio-based IO path for virtio-blk. >>> >>> Why make it optional? >> >> request-based IO path is useful for users who do not want to bypass >> the IO scheduler in guest kernel, e.g. users using spinning disk. >> For users using fast disk device, e.g. SSD device, they can use >> bio-based IO path. > > OK I guess but then it should be per-device. There could be > a mix of slow and fast disks :)
Yes, per-device might be useful. There are issues which need solving. - How do we tell the drive which IO path to use - Device add some flag - Old qemu/lkvm can not turn this feature on - Through /sys filesystem attribute - How do we handle the switch from one path to anther.
So, let's add the per-device feature later.
-- Asias
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