[Mauiusers] Another MAXPROC query

Lennart Karlsson Lennart.Karlsson at nsc.liu.se
Thu Nov 23 08:57:38 MST 2006


Gianfranco Sciacca said:
> I use MAXPROC to limit the number of running or active state and to
> this  end, I have the following settings in maui.cfg:
>
> # Any user allowed 50 jobs in running+priority accrual state
> USERCFG[DEFAULT]        FSTARGET=20+    MAXPROC=50
>
> # No queue stuffing when people have exceeded the MAXPROC values
> JOBPRIOACCRUALPOLICY    FULLPOLICY
>
> This seemed to have worked reasonably well for some time and any user
> exceeding the 50 limit would have the excess jobs placed in the
> "Blocked" status. Now a user came along yesterday submitting a couple
> thousand of jobs to a low priority PBS queue, but these show up in the
>  "Idle" status instead and are accruing priority.

	.
	.
	.

> Do I have a misunderstanding of the MAXPROC & JOBPRIOACCRUALPOLICY
> settings? 



Well, you do not tell how many processors are used by the user's
running jobs?

Your user may use 49 processors in her/his running jobs and still
have many thousands of unblocked and queued jobs, if each job
asks for only one processor. But as soon as there are 50 processors
used, all the queued jobs will get blocked.

So, all the needed processors of the queued jobs are not added
together with the processors of the running jobs. Instead, the
needed resources of each queued job is compared with the processors
of the running jobs, one queued job at at time.

You need to change your first comment

	# Any user allowed 50 jobs in running+priority accrual state

to

	# Any user allowed 50 jobs in running state

Does this explanation answer your question?

If you want to also limit the number of priority accrual jobs
for a user, you may add a MAXIJOB declaration:

	USERCFG[DEFAULT]        FSTARGET=20+    MAXPROC=50 MAXIJOB=10

Only ten jobs will be accruing priority, the others will be blocked.

Best regards,
-- Lennart Karlsson <Lennart.Karlsson at nsc.liu.se>
   National Supercomputer Centre in Linkoping, Sweden
   http://www.nsc.liu.se




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