Re: Improving SliTaz Performance as a Virtual Machine Guest and Reducing Power Consumption

[Christophe Lincoln <pankso@xxxxxxxxxx>]

> Greetings,

Yep,
 
> For the context of this email, I am running VirtualBox 2.1.4 on a
> Windows XP host, with an idle "justX" SliTaz as the VirtualBox guest.
> 
> While running SliTaz as a guest in a virtual machine, CPU usage on my
> VM host is spiked, even when SliTaz is idle.  On my VirtualBox host,
> CPU usage for VirtualBox ranges around 90-99% (you exact percentage,
> though, may vary based on your processor speed and number of cores).
> Based on some work I've done, the enabling CONFIG_NO_HZ in the kernel
> configuration appears to address this issue.  Below are some
> high-level performance comparisons--
> 
> slitaz-cooking-justX (February 28, 2009)
>  * 90-99% CPU usage on the host while the guest is idle
> 
> slitaz-tickless (based on the "justX" flavor)
>  * 5-15% CPU usage on the host while the guest is idle

Realy nice... I also tested the ISO without any issues.

> In addition to improving VM performance, CONFIG_NO_HZ can also reduce
> power consumption and heat output on "real" hardware, as noted by
> Phoronix (see references at the end).
> 
> I have uploaded the ISO image used for this comparison to
> http://users.zoominternet.net/~rcx/slitaz-tickless.iso .  While
> booting this ISO, the message "Switched to NOHz mode on CPU#0" can be
> seen.  I have also been running this CONFIG_NO_HZ-enabled kernel on
> "real" hardware and have not yet observed any negative impacts.
> 
> Considering the large difference in performance, I think there would
> be benefit in enabling CONFIG_NO_HZ in the default SliTaz kernel.  Is
> this something that would be possible to incorporate?

Yes maybe. For now we are going to release a new stable version at the
of the mounth. So this kind of change must wait a bit...

> Thank you,
> Matthew

- Christophe

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