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Date: Wed, 04 Aug 2010 09:39:12 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with
	Linux 2.6.35?
References: <4C586CF9.7030206@redhat.com> <4C588804.5060803@redhat.com>
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>, kvm@vger.kernel.org, qemu-devel@nongnu.org, "Richard W.M. Jones" <rjones@redhat.com>, Avi Kivity <avi@redhat.com>, Gerd Hoffmann <kraxel@redhat.com>

On 08/04/2010 09:22 AM, Paolo Bonzini wrote:
> On 08/04/2010 04:00 PM, Gleb Natapov wrote:
>>> 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.
>>>
>> May be. Can floppy be 100M?
>
> Well, in theory you can have 16384 bytes/sector, 256 tracks, 255 
> sectors, 2 heads... that makes 2^(14+8+8+1) = 2 GB. :)  Not sure the 
> BIOS would read such a beast, or SYSLINUX.
>
> By the way, if libguestfs insists for an initrd rather than a CDROM 
> image, it could do something in between and make an ISO image with 
> ISOLINUX and the required kernel/initrd pair.
>
> (By the way, a network installation image for a typical distribution 
> has a 120M initrd, so it's not just libguestfs.  It is very useful to 
> pass the network installation images directly to qemu via 
> -kernel/-initrd).

We could make kernel an awful lot smarter but unless we've got someone 
just itching to write 16-bit option rom code, I think our best bet is to 
try to leverage a standard bootloader and expose a disk containing the 
kernel/initrd.

Otherwise, we just stick with what we have and deal with the performance 
as is.

Regards,

Anthony Liguori

>
> Paolo