Hi,
Yesterday I asked a couple of questions regarding Class Scheduling under
Tru64. I didn't get any responces from folks using the feature "in the
real world", but Paul Henderson (henderson_at_unx.dec.com) from the Tru64
Unix Engineering group gave me some good answers.
Here's what I learned:
1. Class scheduling is used to set limits on the amount of processor
time that a class can use. The class can use up to that percentage.
2. Classes can be groupings of user IDs (UID), group IDs (GID), process
IDs (PID), and session IDs.
3. Classes are defined with a percentage of cpu, with the max being 100%.
On an SMP system, the max is 100% (it is NOT (cpus*100%)).
4. You can configure the class scheduling subsystem to allow classes to
use more CPU time than their limits, if there are idle CPU cycles.
5. And the $64,000 answer: If you allow classes to use additional idle
time, and you configure a class with 0% cpu time, it should run only
when there is idle time on the system.
Thanks again to Paul.
Original Question:
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> I've been thinking about giving class scheduling, introduced in DU 4.0d,
> a shot to try to control some interactive analysis processes on one of
> my production servers. The desire is to limit the processor time given
> to these interactive tasks, to retain the bulk of the CPU time for batched
> analysis.
>
> I've got a couple of questions:
>
> 1. Does it work? Are there any big nasty gotchas?
>
> 2. The classes are defined by a percentage of CPU time. On an SMP system,
> with say eight processors, is the max 100% or 800%?
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Tom
--
+-----------------------------------+---------------------------------+
| Tom Webster | "Funny, I've never seen it |
| SysAdmin MDA-SSD ISS-IS-HB-S&O | do THAT before...." |
| webster_at_ssdpdc.lgb.cal.boeing.com | - Any user support person |
+-----------------------------------+---------------------------------+
| Unless clearly stated otherwise, all opinions are my own. |
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Received on Thu Jun 24 1999 - 20:07:03 NZST