Re: [Xen-users] poor harddisk performance HVM domain (Windows 2003 guest)

[Andy Clayton <xen.nospam@xxxxxxxxxx>]

Javier Guerra wrote:
> On Sunday 07 May 2006 8:37 am, Joost van den Broek wrote:
>   
> > It even gets worse when installing and using Ubuntu HVM, can't enable DMA
> > for the QEMU harddisk, resulting in a very slow +-3.5MB/s read. Isn't there
> > any way to resolve this?
> >     
> qemu's HD emulation is very primitive; no DMA, no LBA48.  but it shouldn't be 
> such slow, since the real device (in dom0) does have DMA.  of course, the 
> best solution is still in the future, when a HVM domain would accept special 
> paravirtualized drivers for HD and network.  those will be needed to get 
> better performance for windows.
> PD, the newest version of qemu does have both DMA and LBA48, but i think 
> nobody has bothered porting it to Xen
>   
> ------------------------------------------------------------------------
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users
Gah! I missed the reply to all button.  Some have already replied, but 
anyways...
If there is interest in a patch with LBA48 stuff ported over I can post 
it.  I am not sure about DMA, but LBA48 falls in easily and seems to 
work fine.
Andy Clayton

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users