Re: [Qemu-devel] QEMU/NEMU boot time with several x86 firmwares

[Stefano Garzarella]

Hi Philippe,

On Wed, Dec 5, 2018 at 1:26 PM Philippe Mathieu-Daudé <address@hidden> wrote:
>
> Hi Stefano,
>
> On 3/12/18 17:35, Stefano Garzarella wrote:
> > On Mon, Dec 3, 2018 at 4:44 PM Rob Bradford <address@hidden> wrote:
> >>
> >> Hi Stefano, thanks for capturing all these numbers,
> >>
> >> On Mon, 2018-12-03 at 15:27 +0100, Stefano Garzarella wrote:
> >>> Hi Rob,
> >>> I continued to investigate the boot time, and as you suggested I
> >>> looked also at qemu-lite 2.11.2
> >>> (https://github.com/kata-containers/qemu) and NEMU "virt" machine. I
> >>> did the following tests using the Kata kernel configuration
> >>> (
> >>> https://github.com/kata-containers/packaging/blob/master/kernel/configs/x86_64_kata_kvm_4.14.x
> >>> )
> >>>
> >>> To compare the results with qemu-lite direct kernel load, I added
> >>> another tracepoint:
> >>> - linux_start_kernel: first entry of the Linux kernel
> >>> (start_kernel())
> >>>
> >>
> >> Great, do you have a set of patches available that all these trace
> >> points. It would be great for reproduction.
> >
> > For sure! I'm attaching a set of patches for qboot, seabios, ovmf,
> > nemu/qemu/qemu-lite and linux 4.14 whit the tracepoints.
> > I'm also sharing a python script that I'm using with perf to extract
> > the numbers in this way:
> >
> > $ perf record -a -e kvm:kvm_entry -e kvm:kvm_pio -e
> > sched:sched_process_exec -o /tmp/qemu_perf.data &
> > $ # start qemu/nemu multiple times
> > $ killall perf
> > $ perf script -s qemu-perf-script.py -i /tmp/qemu_perf.data
> [...]
> Good stuff. At some point I'd like to have such scripts in the QEMU
> repository to run perf tests on a regular basis (eventually keep those
> metrics somewhere) to be able to catch when we add code that add
> timeoutes and increase boot time.

Thanks for your feedback, maybe we need a version of SeaBIOS and Linux
kernel compiled with the probes.
I'll keep you update.

Cheers,
Stefano

>
> Regards,
>
> Phil.



--
Stefano Garzarella
Red Hat