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

[Avi Kivity <avi@redhat.com>]

  On 08/04/2010 08:46 PM, Richard W.M. Jones wrote:
> On Wed, Aug 04, 2010 at 07:36:04PM +0300, Avi Kivity wrote:
>> 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.
> We had some discussion of this upstream&  decided to do this.  It
> should save the time it takes for the guest kernel to unpack the
> initrd, so maybe another second off boot time, which could bring us
> ever closer to the "golden" 5 second boot target.
>

Great.  IMO it's the right thing even if initrd took zero time.

> It's not trivial mind you, and won't happen straightaway.  Part of it
> is that it requires reworking the appliance builder (a matter of just
> coding really).  The less trivial part is that we have to 'hide' the
> CD device throughout the publically available interfaces.  Then of
> course, a lot of testing.
>
> I will note that virt-install uses the -initrd interface for
> installing guests (large initrds too).  And I've talked with a
> sysadmin who was using -kernel and -initrd for deploying VM hosting.
> In his case he did it so he could centralize kernel distribution /
> updates, and have the guests use /dev/vda == filesystem which made
> provisioning easy [for him -- I would have used libguestfs ...].

We still plan to improve pio speed.

(note a few added seconds to guest install or bootup is not such a drag 
compared to the hit on an interactive tool like libguestfs).

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