Re: [Qemu-discuss] NO Change in Booting time with different resources

[Jakob Bohm]

On 04/05/2016 11:16, Ashkan Taslimi wrote:
> Hi guys,
>
> I just test booted an image with qemu with the settings in the table 
> below .
>
> Why do I get more time when I am using more CPU/MEM?
> This is strange!
This also happens on real hardware!

When booting almost any OS, most of the time is spent doing
the following:
  - Doing I/O to initialize devices (same).
  - Doing I/O to show start up messages (same).
  - Doing a lot of I/O to load programs and their configuration
   from(virtual) disk.
  - Detecting and initializing each CPU (more for each CPU).
  - Synchronizing between CPUs (less if one CPU).
  - Setting up memory management structures (more if more
   memory).
  - Setting up per CPU memory management structures (more
   if more memory and/or CPUs).


> The command I used:
> *qemu-system-x86_64 -hda debian.img -m 4G -smp 2*
>
>
> Thanks in advance!
> _________________________________________________________________
>
>
> *CPU*   *MEM*   *Time to boot*
> 1       1       47
> 1       2       50
> 2       4       48
> 2       8       54
> 4       16      56
> KVM
>         
>         18



Enjoy

Jakob
--
Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
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