Subject: Re: Further scheduler changes
To: Daniel Sieger <dsieger@TechFak.Uni-Bielefeld.DE>
From: David Laight <>
List: tech-kern
Date: 09/19/2006 18:14:59
On Tue, Sep 19, 2006 at 01:30:56AM +0200, Daniel Sieger wrote:
> Hi all,
> ok, I would like to get some suggestions about how to further improve
> the scheduler. The first thing that comes to my mind is to design a
> general scheduling API that allows for the implementation of different
> algorithms and/or models. FreeBSD did a similar job, IIRC. So, the
> next steps would be i) to define the API itself and ii) to separate
> the traditional 4.4BSD scheduler from kern_synch.c.
> Any comments/suggestions?

One 'really useful feature' that any change should allow for is
process affinities (ie tying a process to a physical cpu).

You'll also notice that the current scheduler recalculates the priority
of every process on every tick.  This a waste of cpu (and cache line
entries).  The priorites of non-runnable processes can be changed
when they become runnable - using the elapsd time since the last


David Laight: