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

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Hi Stefano,

On 3/12/18 17:35, Stefano Garzarella wrote:
> On Mon, Dec 3, 2018 at 4:44 PM Rob Bradford <robert.bradford@intel.com> 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.

Regards,

Phil.