<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Hi,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">my Slurm cluster has a dozen machines configured as follows:</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">NodeName=foobar01 CPUs=80 Boards=1 SocketsPerBoard=2 CoresPerSocket=20 ThreadsPerCore=2 RealMemory=257243 State=UNKNOWN<br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">and scheduling is:</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"># SCHEDULING<br>SchedulerType=sched/backfill<br>SelectType=select/cons_tres<br>SelectTypeParameters=CR_Core<br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">My problem is that only half of the logical cores are used when I run a computation.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Let me explain: I use R and the package 'batchtools' to create jobs. All the jobs are created under the hood with sbatch. If I log in to all the machines in my cluster and do a 'htop', I can see that only half of the logical cores are used. Other methods to measure the load of each machine confirmed this "visual" clue.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">My jobs ask Slurm for only one cpu per task. I tried to enforce that with the -c 1 but it didn't make any difference.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Then I realized there was something strange: </div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">when I do scontrol show job <jobid>, I can spot the following output:</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">   NumNodes=1 NumCPUs=2 NumTasks=0 CPUs/Task=1 ReqB:S:C:T=0:0:*:*<br>   TRES=cpu=2,node=1,billing=2<br>   Socks/Node=* NtasksPerN:B:S:C=0:0:*:2 CoreSpec=*<br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">that is each job uses NumCPUs=2 instead of 1. Also, I'm not sure why TRES=cpu=2</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Any idea on how to solve this problem and have 100% of the logical cores allocated?</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Best regards,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">David</div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"></div></div></div></div></div></div></div></div>