On 22 Apr 2009, at 12:27 PM, Rob Fay wrote:
> Graeme Stewart wrote:
>> On Tue, Apr 21, 2009 at 5:05 PM, Sam Skipsey
>> <[log in to unmask]> wrote:
>>> 2009/4/21 Graeme Stewart <[log in to unmask]>:
>>>
>>>> I have one final question, which is about fairshare, does anyone
>>>> understand the difference between DEDICATEDPS and DEDICATEDPES in
>>>> maui? I want to make sure that fairshares are calculated based on
>>>> wallclock times, not on cpu consumption times. The maui manual
>>>> describes FSPOLICY (http://tinyurl.com/cjgpba), but doesn't really
>>>> explain which setting does what.
>>>>
>>> I believe that DEDICATEDPS scales according to processor-seconds
>>> (that
>>> is number of processors * time), and DEDICATEDPES scales according
>>> to
>>> "effective processors"*seconds, and is designed to cope with
>>> situations where, say, you're using 4 of the 8 cores on a machine,
>>> but
>>> all of the memory. DEDICATEDPES would assign you an "effective
>>> processors" of 8, not 4, since you're using more memory than you
>>> should be (in fact, you're using all the memory in the box, so
>>> you're
>>> effectively using 8 processors).
>> Yes, this I understand. But if you have a job that user 1 core and
>> sleeps for an hour does it get charged for its hour or not? And does
>> the setting of DEDICATEDPES/DEDICATEDPS affect this?
> Yes, it does get charged for its hour, and no, the setting of
> DEDICATEDPS or DEDICATEDPES doesn't change that. DEDICATED usage
> tracks what the scheduler has dedicated to the job, not what the job
> has consumed, so it is (essentially) walltime. A 1 core job that
> sleeps for an hour will have a dedicated fairshare usage of 1 proc-
> hour. A 4 processor job that runs four lots of sleep for an hour
> will have a dedicated fairshare usage of 4 proc-hours.
>
> I believe the alternative is UTILIZEDPS, which tracks actual usage
> of processor time (although the maui manual is typically vague on
> this).
Right! I think this was the key piece of information which was missing
(vague indeed!).
On hammercloud, it looks like there was a submission problem this
morning (maybe WMS issue?). Experts are checking, but it seems not
many jobs were created. More news as I get it.
Cheers
Graeme
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