Re: [SeaBIOS] [RFC 0/2] QEMU fw_cfg dma interface

[Marc Marí]

On Tue, 21 Jul 2015 12:47:47 -0400
"Kevin O'Connor"  wrote:
> On Tue, Jul 21, 2015 at 06:06:09PM +0200, Marc Marí wrote:
> > These patches, with the support in QEMU (patches in the QEMU mailing
> > list) make the Linux kernel setup and boot approximately 10x faster.
>
> Thanks.  How do the timings with this support compare with the qboot
> and seabios+cbfs runs?
>
> -Kevin

The boot time for a standard SeaBIOS (with the default configuration
options) is this:

QEMU startup time: .032
BIOS startup time: .154
fw_cfg setup time: .375
Total time: .562

The boot time for a standard SeaBIOS with the CBFS patch is this:

QEMU startup time: .036
BIOS startup time: .184
Kernel setup time: .003
Total time: .223

The boot time for a standard SeaBIOS with the fw_cfg DMA interface patch
is this:

QEMU startup time: .036
BIOS startup time: .140
Kernel setup time: .026
Total time: .202

The time of getting the kernel image ready and boot it has improved by
10x, although the time is not as good as with CBFS.

But the BIOS time, with all the setup from the fw_cfg interface, has
also improved.

There are some pending optimizations in the host and in this code that
can make these times even better. I'll compare things more in detail
when these are done.

Thanks
Marc