Re: [Announce] [patch] Modular Scheduler Core and Completely Fair Scheduler [CFS]

[Davide Libenzi <davidel@xmailserver.org>]

On Thu, 19 Apr 2007, Ingo Molnar wrote:

> i disagree that the user 'would expect' this. Some users might. Others 
> would say: 'my 10-thread rendering engine is more important than a 
> 1-thread job because it's using 10 threads for a reason'. And the CFS 
> feedback so far strengthens this point: the default behavior of treating 
> the thread as a single scheduling (and CPU time accounting) unit works 
> pretty well on the desktop.
> 
> think about it in another, 'kernel policy' way as well: we'd like to 
> _encourage_ more parallel user applications. Hurting them by accounting 
> all threads together sends the exact opposite message.

There are counter argouments too. Like, not every user knows if a certain 
process is MT or not. I agree though that doing accounting and fairness at 
a depth lower then USER is messy, and not only for performance.


- Davide


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