Re: [SeaBIOS] [PATCH] fix two issues with virtio-blk

[Gleb Natapov]

On Sun, May 16, 2010 at 06:14:57PM +0200, Sebastian Herbszt wrote:
> > >              The performance without native support
> > >
> > > (emulation in BIOS) could be worse due to the additional
> > > overhead. How much performance
> > > is lost if the 512 byte logical sector size emulation is done in virtio (for reads
> > > it could behave like a read ahead buffer) ?
> >
> > Low performance of BIOS emulation is not a concern. BIOS is used only by
> > boot loaders. OSes access disk without BIOS help.
>
> Legacy OS or OS installers tend to use BIOS disk access too.

So what choice legacy OS has when faced with drives with 4K logical
block size? Either it will not work, or will works slightly slower. (I
doubt that the slowdown will be actually measurable).