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Re: [Qemu-devel] SeaBIOS booting time optimization
From: |
Gerd Hoffmann |
Subject: |
Re: [Qemu-devel] SeaBIOS booting time optimization |
Date: |
Thu, 22 Nov 2018 12:51:35 +0100 |
User-agent: |
NeoMutt/20180716 |
On Thu, Nov 22, 2018 at 12:08:55PM +0100, Stefano Garzarella wrote:
> Hi,
> I continued to investigate how to reduce the boot time with SeaBIOS
> and QEMU when it used with linuxboot_dma.bin (-kernel parameter).
> I reached ~12ms with a SeaBIOS configuration (attached) where I
> disabled debug output, all Hardware support (except SMM & MTRRs) and I
> applied a small patch to disable VGA setup and console (attached).
Is there any difference to "qemu -vga none" ?
> Samuel, I put also the total time to userspace (linux_start_user)
> adding a probe in the kernel_init() and when I disabled the VGA in the
> SeaBIOS I noticed also a speed up in the kernel boot phase.
Might come from linux 16bit boot code scanning vgabios for available
video modes (for vga=<mode> cmdline arg).
> Another approach that I tried, obtaining similar results, is to
> recognize the linuxboot_dma.bin at runtime, then skip
> device_hardware_setup(), enable_vga_console(), and vgarom_setup().
Hmm, tricky.
linuxboot_dma.bin just registers a boot entry, so with "qemu -kernel
-boot menu=on" you can still get a boot menu, and the direkt kernel boot
is one menu item there. So you can't know for sure whenever a direct
kernel boot will happen or not.
So, I think at minimum we should make this depend on both linuxboot_dma
and boot menu disabled.
cheers,
Gerd
- Re: [Qemu-devel] SeaBIOS booting time optimization, (continued)
- Re: [Qemu-devel] SeaBIOS booting time optimization, Gerd Hoffmann, 2018/11/19
- Re: [Qemu-devel] SeaBIOS booting time optimization, Stefano Garzarella, 2018/11/19
- Re: [Qemu-devel] SeaBIOS booting time optimization, Stefan Hajnoczi, 2018/11/19
- Re: [Qemu-devel] SeaBIOS booting time optimization, Gerd Hoffmann, 2018/11/19
- Re: [Qemu-devel] SeaBIOS booting time optimization, Stefano Garzarella, 2018/11/19
- Re: [Qemu-devel] SeaBIOS booting time optimization, Gerd Hoffmann, 2018/11/20
- Re: [Qemu-devel] SeaBIOS booting time optimization, Stefano Garzarella, 2018/11/20
- Re: [Qemu-devel] SeaBIOS booting time optimization, Gerd Hoffmann, 2018/11/20
- Re: [Qemu-devel] SeaBIOS booting time optimization, Stefano Garzarella, 2018/11/22
- Re: [Qemu-devel] SeaBIOS booting time optimization,
Gerd Hoffmann <=
- Re: [Qemu-devel] SeaBIOS booting time optimization, Stefano Garzarella, 2018/11/22
- Re: [Qemu-devel] SeaBIOS booting time optimization, Gerd Hoffmann, 2018/11/23
- Re: [Qemu-devel] SeaBIOS booting time optimization, Stefano Garzarella, 2018/11/23
- Re: [Qemu-devel] SeaBIOS booting time optimization, Kevin O'Connor, 2018/11/23
- Re: [Qemu-devel] SeaBIOS booting time optimization, Stefano Garzarella, 2018/11/23
- Re: [Qemu-devel] [SeaBIOS] SeaBIOS booting time optimization, Kevin O'Connor, 2018/11/20
- Re: [Qemu-devel] [SeaBIOS] SeaBIOS booting time optimization, Steve Douthit, 2018/11/20
- Re: [Qemu-devel] [SeaBIOS] SeaBIOS booting time optimization, Stefano Garzarella, 2018/11/20
- Re: [Qemu-devel] [SeaBIOS] SeaBIOS booting time optimization, Stefan Berger, 2018/11/21
- Re: [Qemu-devel] [SeaBIOS] SeaBIOS booting time optimization, Kevin O'Connor, 2018/11/27