Re: Stolen and degraded time and schedulers

Rik van Riel
2007-03-14T19:53:33Z

Jeremy Fitzhardinge wrote:

>> How is time quantum getting stolen less important? Time quantum
>> getting stolen results directly in more unnecessary context switches
>> since we might steal the entire timeslice before the process even ran.
>
> It doesn't matter why you didn't get the time;

Oh, but it does.

System administrators can use steal time the same way they
use iowait time: to spot bottlenecks on their systems.

If you have a lot of iowait time, you know you want either
faster IO or more memory.

If you have a lot of steal time, you know you need to spread
your virtual machines over more CPUs.

Steal time allows you to see the difference between a busy
system and an overloaded system.

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