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<p>Well, I know of no way to 'throttle' running jobs. Once they are
out the gate, you can't stop them from leaving..</p>
<p>That said, your approach of setting arraytaskthrottle is just
what you want for any pending jobs.</p>
<p>As a preventative measure, I imagine you could set the default to
1 and then change it with a job_submit script.</p>
<p>As far as currently running tasks, well, you have to figure that.
You could kill/requeue them, but that can break things for the
user. If their code supports it, they could checkpoint/restart as
part of the process.</p>
<p>You can suspend them, but they still sit on the node waiting to
be resumed, but the node resources may get assigned to other jobs
while they wait to resume.</p>
<p>Brian Andrus<br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 9/22/2020 2:33 PM, Ransom, Geoffrey
M. wrote:<br>
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cite="mid:90d1ce76fe814f9eafd588c56cee577c@APLEX03.dom1.jhuapl.edu">
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hello<o:p></o:p></p>
<p class="MsoNormal"> We had a user post a large number of
array jobs with a short actual run time (20-80 seconds, but
mostly to the low end) and slurmctld was falling behind on RPC
calls trying to handle the jobs. It was a bit awkward trying
to slap arraytaskthrottle=5 on each of the queued array jobs
while slurmctld was having issues handling the RPC load.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m looking to make a QOS with
MaxJobsPerUser=50 set that I can quickly add to a user to
throttle their jobs but..<o:p></o:p></p>
<p class="MsoListParagraph"
style="text-indent:-.25in;mso-list:l0 level1 lfo1"><!--[if !supportLists]--><span
style="mso-list:Ignore">1)<span style="font:7.0pt
"Times New Roman"">
</span></span><!--[endif]-->Adding a QOS to the user does
not affect queued jobs so I still have to get all of the users
jobids and modify each on directly.<o:p></o:p></p>
<p class="MsoListParagraph"
style="text-indent:-.25in;mso-list:l0 level1 lfo1"><!--[if !supportLists]--><span
style="mso-list:Ignore">2)<span style="font:7.0pt
"Times New Roman"">
</span></span><!--[endif]-->I queued up a test job with the
QOS set and it is still running 100 jobs at a time (what I set
arraytaskthrottle to in the job) and not limiting the “user”
to 50 jobs.<o:p></o:p></p>
<p class="MsoListParagraph"
style="text-indent:-.25in;mso-list:l0 level1 lfo1"><!--[if !supportLists]--><span
style="mso-list:Ignore">3)<span style="font:7.0pt
"Times New Roman"">
</span></span><!--[endif]-->I tried adding the FLAG
OverPartQOS to see if that changed the behavior, but it did
not seem to do anything. My test cluster I ran this on doesn’t
have any other QOSes defined but our production cluster does
have a partition QOS in place limiting single users to about
80% of the CPUs with MaxTRESPerUser.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Is there a quick way to limit how many jobs
a specific user can run at one time on the cluster or in a
partition if we need to throttle them back in an emergency but
we don’t want to flat out kill their jobs?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks. <o:p></o:p></p>
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