On Wed, Nov 17, 1999 at 09:14:26AM +0100, Herbert Wengatz 42850 wrote:
> +> One thing you might want to do in the 10 game servers scenario is
> +> control how much CPU time each server is allowed to use. You can do
> +> this with my hierarchical fair scheduler (link below). For example,
> +> you can say things like "this group of processes is twice as important
> +> as that group" and it'll be guaranteed twice as much CPU time. Within
> +> each group processes are scheduled by the standard scheduler.
>
> I can see no problem... Why should one introduce hierachical
> scheduling, when you can set priorities with "nice" ?
"Nice" gives you fairly little control and no guarantees. If it does
the job for you then you should use it, but there are situations where
it isn't enough.
Here is the standard scenario: an ISP allows customers to run
computationally expensive scripts on a server. Customer A is paying
twice as much as customer B, so he expects twice as much CPU time. A
fair scheduler (fair is a technical term here) can guarantee
proportional allocation of CPU time. A hierarchical fair scheduler
allows you to do this on several levels, e.g. A might be a reseller
that further partitions the CPU time among his own customers. At the
bottom of the hierarchy you still have all the flexibility of the
standard scheduler - RT processes, nice values, etc.
This is not as theoretical as it sounds - some people actually want to
do this.
Regards,
Borislav
-
Linux SMP list: FIRST see FAQ at http://www.irisa.fr/prive/dmentre/smp-howto/
To Unsubscribe: send "unsubscribe linux-smp" to [EMAIL PROTECTED]
