Re: [SeaBIOS] Reducing SeaBIOS kernel entry time

[Kevin O'Connor]

On Fri, Jul 03, 2015 at 10:33:56AM +0100, Stefan Hajnoczi wrote:
> Hi,
> qboot (https://github.com/bonzini/qboot) is a stripped down firmware
> providing only what is needed to boot a Linux kernel on x86.  I wonder
> if there is room to achieve similar results with SeaBIOS for the
> lightweight virtual machine use case.
>
> The goal is to enter the kernel within 20 milliseconds.  (That's the
> number I measured with qboot.)
>
> Kevin: Have you looked at SeaBIOS startup time and do you think this
> use case is within the scope of what SeaBIOS is intended for?
>
> Marc is beginning to profile boot times and any pointers would be helpful.

Hi Stefan,

I took a look a month or so ago:

http://article.gmane.org/gmane.comp.emulators.kvm.devel/136207

Last test I ran I had SeaBIOS down to 16ms (not including the time to
deploy or jump to the linux kernel).  More reductions are also
possible - the above was just with Kconfig settings.

Let me know if you want more info on how I did that.

-Kevin

Reducing SeaBIOS kernel entry time

[Stefan Hajnoczi]

On Fri, Jul 3, 2015 at 2:13 PM, Kevin O'Connor  wrote:
> On Fri, Jul 03, 2015 at 10:33:56AM +0100, Stefan Hajnoczi wrote:
> > Hi,
> > qboot (https://github.com/bonzini/qboot) is a stripped down firmware
> > providing only what is needed to boot a Linux kernel on x86.  I wonder
> > if there is room to achieve similar results with SeaBIOS for the
> > lightweight virtual machine use case.
> >
> > The goal is to enter the kernel within 20 milliseconds.  (That's the
> > number I measured with qboot.)
> >
> > Kevin: Have you looked at SeaBIOS startup time and do you think this
> > use case is within the scope of what SeaBIOS is intended for?
> >
> > Marc is beginning to profile boot times and any pointers would be helpful.
>
> Hi Stefan,
>
> I took a look a month or so ago:
>
> http://article.gmane.org/gmane.comp.emulators.kvm.devel/136207
>
> Last test I ran I had SeaBIOS down to 16ms (not including the time to
> deploy or jump to the linux kernel).  More reductions are also
> possible - the above was just with Kconfig settings.
>
> Let me know if you want more info on how I did that.

That sounds interesting.  Do you have a .config or git branch?

Stefan