Re: [Xen-devel] pvops upstream status

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Tue, 17 Jun 2014, Sander Eikelenboom wrote:
> Tuesday, June 17, 2014, 3:34:17 PM, you wrote:
> 
> > On 06/17/2014 12:55 PM, Fabio Fantoni wrote:
> >> Il 17/06/2014 11:52, Juergen Gross ha scritto:
> >>> Hi,
> >>>
> >>> I'd like to update the wiki page
> >>>
> >>> http://wiki.xenproject.org/wiki/XenParavirtOps
> >>>
> >>> regarding the current status of the pvops kernel. I've just started to
> >>> collect the missing bits and who is working on them. Up to now I have a
> >>> SUSE internal list, some data from Konrad, and, of course, the EFI
> >>> patches sent by Daniel last week:
> >>>
> >>> - EFI support (patches posted by Daniel Kiper on 13.06.2014)
> >>> - use of PAT (i.e. WC memory type) not possible
> >>> - microcode loader (runtime)
> >>> - 500Gb+ support
> >>> - expected to be dead (under Xen) code cannot be easily verified to
> >>>   indeed be dead (e.g. IOMMU, PCI ATS, PRI, and PASID), leaving the
> >>>   risk of bad interaction between hypervisor and Dom0 if a new, active
> >>>   user of that code appears and goes unnoticed
> >>> - user mode pvclock
> >>> - possibly not suitable for pre-4.0.1 hypervisor (definitely not as
> >>>   Dom0)
> >>> - blktap (blktap3 replacement stalled)
> >>
> >> I think blktap is no more needed, qdisk of qemu upstream (already used
> >> by xen) has much superior performance.
> >> One my first benchmark of long time ago in attachment.
> 
> > Okay, noted. We'll have to verify that all blktap protocols and
> > scenarios are handled properly and with good performance by qdisk.
> 
> > Thanks, Juergen
> 
> Another benchmark:
> https://events.linuxfoundation.org/sites/events/files/slides/20131025%20-%20Storage%20Performance%20PDF.pdf
> 
> seems to show not that much difference between tapdisk and qdisk (both 
> relatively slow compared to blkback)

qdisk should be a very good replacement, even better than blktap unless
the guest image format is vhd, in that case blktap has better support
for the format.
Of course guest images can be converted to raw or qcow2 using
qemu-img.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel