Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with Linux 2.6.35?

[Anthony Liguori]

On 08/03/2010 11:50 AM, Avi Kivity wrote:
>  On 08/03/2010 07:46 PM, Anthony Liguori wrote:
> > > It doesn't appear to support live migration, or hiding the feature 
> > > for -M older.
> > >
> > > It's not a good path to follow.  Tomorrow we'll need to load 300MB 
> > > initrds and we'll have to rework this yet again.  Meanwhile the 
> > > kernel and virtio support demand loading of any image size you'd 
> > > want to use.
> >
> >
> > firmware is totally broken with respect to -M older FWIW.
>
> Well, then this is adding to the brokenness.
>
> fwcfg dma is going to have exactly one user, libguestfs.  Much better 
> to have libguestfs move to some other interface and improve are 
> users-to-interfaces ratio.

BTW, the brokenness is that regardless of -M older, we always use the 
newest firmware.  Because always use the newest firmware, fwcfg is not a 
backwards compatible interface.

Migration totally screws this up.  While we migrate roms (and correctly 
now thanks to Alex's patches), we size the allocation based on the 
newest firmware size.  That means if we ever decreased the size of a 
rom, we'd see total failure (even if we had a compatible fwcfg interface).

Regards,

Anthony Liguori