--On March 22, 2007 9:25:27 AM +0100 Eric Thomas <[log in to unmask]> wrote:


> Ah yes, and I recompile all my Linux guests to set HZ to something
> sensible, like 100. A typical 2-way Linux guest request 3,000 timer
> interrupts per second to try and keep the time accurate, and these are
> expensive virtual interrupts. If you have 5 Linux guests, that's 15,000
> timer interrupts per second and you can start ordering a processor
> upgrade just to count microseconds on an industrial scale. This ought to
> be a kernel startup option so that you can change it without recompiling.

HZ is used as a macro allover in the kernel, not a variable.  It's used in 
a lot of places that need to be static, not computed, values, as well. 
Unlikely to see this happen.  Used to be 100 was the default on x86 
machines.  I noticed 2.6 seems to have pushed that to 250 or so.

>
>   Eric
>



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