> On 16 Nov 2017, at 12:37, Gareth Roy <[log in to unmask]> wrote:
>
> Hi All,
>
> We're currently seeing multithreaded payloads from LHCb that are causing high loads on some of our batch farm (although contained somewhat by cgroups). It appears a user has compiled some code enabling openmp (see runjob script below), so the job is attempting to start and run 32 threads per job.
>
> Is anyone else seeing these payloads? We're reasonably well protected via cgroups but it does mean that this user has 32 threads sharing a single cpu share so the jobs may take a while to complete (and potential waste cpu time).
You should report the jobs to LHCb (GGUS ticket or mail the GEOC: [log in to unmask] ) and then we’ll escalate this with the user in question. We’re not happy with users submitting multiprocessor jobs to single processor slots and do follow it up.
Cheers
Andrew
> ================================================
> # cat runjob.sh
> #!/bin/bash
> set -euo pipefail
> IFS=$'\n\t'
> set -x
>
> ls -la /cvmfs/
> source /cvmfs/sft.cern.ch/lcg/external/gcc/6.2.0/x86_64-slc6-gcc62-opt/setup.sh
> g++ -o energy_test -std=c++1z -O3 -Wall -I. energy_test.cpp -fopenmp
>
> ENERGY_TEST_SEED=$(od -N 6 -t uL -An /dev/urandom | tr -d " ")
> echo "Using seed ${ENERGY_TEST_SEED}"
> ./energy_test --max-events=500000 --max-permutation-events-1=$1 --seed=$ENERGY_TEST_SEED --n-permutations=$2 sample1.txt sample2.txt --permutations-only
>
> [University of Glasgow: The Times Scottish University of the Year 2018]
Cheers
Andrew
--
Dr Andrew McNab
University of Manchester High Energy Physics,
LHCb@CERN (Deputy Computing Coordinator),
and GridPP (LHCb + Tier-2 Evolution)
www.hep.manchester.ac.uk/u/mcnab
Skype: andrew.mcnab.uk
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