Quick win

I got the libguestfs launch time down from 12 seconds to 9 seconds today, 25% faster!

It turns out that the appliance’s BIOS was waiting for 3 seconds for someone to hit [F12] on the imaginary keyboard. A simple patch to bochs BIOS fixes that … This patch benefits everyone using Fedora and virtualization, since all boot times will be reduced by 3 seconds.

This is only the start of the optimizations. I’m pretty certain we can get it down to a 4 or 5 second launch time.

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3 Comments

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3 responses to “Quick win

  1. Of course, if you build the QEMU bios that way, then you lose the advantage of being able to change the boot device when booting the virtual machine. Which is a pretty big loss.

    (Said as the person who finally got fed up enough with it to implement having the functionality :)

  2. rich

    Jeremy yes of course you are right.

    However pressing F12 during the boot of a VM (assuming that is possible — ie. almost certainly not) is a terrible user interface for selecting the boot device for a VM.

    Pressing a magic key was necessary on physical hardware. It’s not now. We can use libvirt or libguestfs and the corresponding higher level / graphical interfaces to change the boot device far more easily.

  3. Pingback: libguestfs launch times « Richard WM Jones

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