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
And I used perf (and two out instructions in the BIOS) to measure the
times:
perf record -a -e kvm:\* -e sched:sched_process_exec
And searching for sched:sched_process_exec, kvm:kvm_entry, pio_write at
0xf5 and pio_write at 0xf4. Out at 0xf5 is the one in "do_boot"
function, and out at 0xf4 is the one just before the jump to the Linux
kernel.
I attach the script I've been using. It can be improved, but it works.
It can be run like this:
sudo ../../results/run_test.sh x86_64-softmmu/qemu-system-x86_64 \
--enable-kvm -kernel /boot/vmlinuz-4.0.8-300.fc22.x86_64 \
-L pc-bios/optionrom/ \
-bios roms/seabios/out/bios.bin -nographic
Thanks
Marc
run_test.sh
Description: application/shellscript
