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

From: Jakob Bohm
Subject: Re: [Qemu-discuss] NO Change in Booting time with different resources
Date: Wed, 4 May 2016 11:28:31 +0200
User-agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.0

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
  - 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


Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark.  Direct +45 31 13 16 10
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