Re: sync guest calls made async on host - SQLite performance

[Avi Kivity <avi@redhat.com>]

On 10/09/2009 09:06 PM, Matthew Tippett wrote:
> Thanks Duncan for reproducing the behavior outside myself and Phoronix.
>
> I dug deeper into the actual syscalls being made by sqlite.  The 
> salient part of the behaviour is small sequential writes followed by a 
> fdatasync (effectively a metadata-free fsync).
>
> As Dustin indicates,
>
>    if scsi is used, you incur the cost of virtualization,
>    if virtio is used, your guests fsyncs incur less cost.
>
> So back to the question to the kvm team.  It appears that with the 
> stock KVM setup customers who need higher data integrity (through 
> fsync) should steer away from virtio for the moment.
>
> Is that assessment correct?
>

Christoph, wasn't there a bug where the guest didn't wait for requests 
in response to a barrier request?

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