Trimming CC list. On Thu, Aug 06, 2015 at 05:53:26PM +0200, Marc Marí wrote: > On Thu, 6 Aug 2015 11:30:43 -0400 > "Kevin O'Connor" <ke...@koconnor.net> wrote: > > On Thu, Aug 06, 2015 at 02:37:45PM +0200, Marc Marí wrote: > > > On Thu, 6 Aug 2015 13:27:16 +0100 > > > Stefan Hajnoczi <stefa...@gmail.com> wrote: > > > > > > > On Thu, Aug 6, 2015 at 12:00 PM, Marc Marí <mar...@redhat.com> > > > > wrote: > > > > > When running a Linux guest on top of QEMU, using the -kernel > > > > > options, this is the timing improvement for x86: > > > > > > > > > > QEMU commit 2be4f242b50a8 and SeaBIOS commit 908a58c1d5ff > > > > > QEMU startup time: .078 > > > > > BIOS startup time: .060 > > > > > Kernel setup time: .578 > > > > > Total time: .716 > > > > > > > > > > QEMU with this patch series and SeaBIOS with this patch series > > > > > QEMU startup time: .080 > > > > > BIOS startup time: .039 > > > > > Kernel setup time: .002 > > > > > Total time: .121 > > > > > > > > Impressive results! > > > > > > > > Is this a fully-featured QEMU build or did you disable things? > > > > > > > > Is this the default SeaBIOS build or did you disable things? > > > > > > > > > > This is the default QEMU configuration I get for my system. It's > > > not a fully-featured QEMU, but it has a lot of things enabled. > > > SeaBIOS has a default configuration (with debugging disabled). > > > > Thanks! > > > > What qemu command-line did you use during testing? Also, do you have > > a quick primer on how to use the kvm trace stuff to obtain timings? > > > > The command line I used is: > > x86_64-softmmu/qemu-system-x86_64 --enable-kvm \ > -kernel /boot/vmlinuz-4.0.7-300.fc22.x86_64 \ > -L pc-bios/optionrom/ \ > -bios roms/seabios/out/bios.bin -nographic
Thanks. One thing that immediately pops up is that even though "-nographic" is used, it looks like QEMU still emulates a VGA device and that device has an option rom that takes several milliseconds to init the display hardware. Adding "-device VGA,romfile=" to the qemu command line will further reduce the boot time by avoiding this hardware init delay. -Kevin
