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

[Avi Kivity <avi@redhat.com>]

  On 08/04/2010 07:30 PM, Avi Kivity wrote:
>  On 08/04/2010 04:52 PM, Anthony Liguori wrote:
>>>>
>>> This is not like DMA event if done in chunks and chunks can be pretty
>>> big. The code that dials with copying may temporary unmap some pci
>>> devices to have more space there.
>>
>>
>> That's a bit complicated because SeaBIOS is managing the PCI devices 
>> whereas the kernel code is running as an option rom.  I don't know 
>> the BIOS PCI interfaces well so I don't know how doable this is.
>>
>> Maybe we're just being too fancy here.
>>
>> We could rewrite -kernel/-append/-initrd to just generate a floppy 
>> image in RAM, and just boot from floppy.
>
> How could this work?  the RAM belongs to SeaBIOS immediately after 
> reset, it would just scribble over it.  Or worse, not scribble on it 
> until some date in the future.
>
> -kernel data has to find its way to memory after the bios gives 
> control to some optionrom.  An alternative would be to embed knowledge 
> of -kernel in seabios, but I don't think it's a good one.
>

Oh, you meant host RAM, not guest RAM.  Disregard.

This is basically my suggestion to libguestfs: instead of generating an 
initrd, generate a bootable cdrom, and boot from that.  The result is 
faster and has a smaller memory footprint.  Everyone wins.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.