OT: renice jobs running for more than 5 minutes

[Rick Stevens]

On 02/22/2016 10:19 AM, Ranjan Maitra wrote:
> Hi,
>
> I am running a fully updated F23 box but this question does not have much to do with Fedora itself, hence the designator and the disclaimer.
>
> I am wanting to run a script which will look at all the jobs that are running and renice all of them which have been on for more than five minutes. (Then I can run the script as a cron job as root and be done with automating the process.)
>
> Are there any suggestions as to how to go about this task efficiently? Actually, before I reinvent the wheel, are there any standard options that already exist and which would be more suitable for me than just to do everything from scratch.

Use the "-o pid,etimes=" options of ps to get the elapsed time of
tasks in seconds. To get a full list, for example, as root:

	ps ax -o pid,uid,etimes=
	...
	21412     0     833
	21499     0  631433
	21541     0     773
	21597  1000     769
	21604  1000     769
	21605  1000     769
	21608  1000     769
	21610  1000     769
	21613  1000     769
	21681  1000     769
	21686  1000     769
	21697  1000     769
	21751  1000     742
	...

(run it as root so you can see ALL of the processes)

As you can see, you get three columns: the first is the PID of the
task, the second is the EUID of the user running it, and the third is
the elapsed time.

So, pull that data into a shell array, look for stuff that has the
second column equal to the user ID you're interested in and the third
column >= 300 seconds and renice the PID in the first column. Note that
I'd avoid renicing any tasks with UIDs < your lowest normal user ID
(typically 100) to keep from starving system tasks.

Hope that helps!
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- Rick Stevens, Systems Engineer, AllDigital    ricks at alldigital.com -
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