Re: [PATCH] x86: Reduce the default HZ value

From: Alan Cox
Date: Thu May 07 2009 - 15:55:10 EST


On Thu, 7 May 2009 14:12:15 -0400 (EDT)
Christoph Lameter <cl@xxxxxxxxx> wrote:

> To get back to the main point: I agree with Alok that the default HZ needs
> to be as low as possible. The remaining justification is the load
> balancing and possible context switching between multiple tasks contenting
> for a processor.
>
> Is it enough if this occurs 100 times per second?

I would like to see evidence that it is, and by evidence I don't mean
"our virtual machine manager runs better" but good evidence that it isn't
affecting performance of any games, applications, video suites etc -
because we know it did in the past.

Even then its pointlessly jumping up and down and changing stuff rather
than fixing the real problem - which is jiffies.

Alan
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