Hi David, I had the same problem time ago when configuring my first server.
Could you try SelectTypeParameters=CR_CPU instead of SelectTypeParameters=CR_Core? Best regards, Rodrigo. On Thu, Oct 8, 2020, 02:16 David Bellot <david.bel...@lifetrading.com.au> wrote: > Hi, > > my Slurm cluster has a dozen machines configured as follows: > > NodeName=foobar01 CPUs=80 Boards=1 SocketsPerBoard=2 CoresPerSocket=20 > ThreadsPerCore=2 RealMemory=257243 State=UNKNOWN > > and scheduling is: > > # SCHEDULING > SchedulerType=sched/backfill > SelectType=select/cons_tres > SelectTypeParameters=CR_Core > > My problem is that only half of the logical cores are used when I run a > computation. > > 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. > 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. > > Then I realized there was something strange: > when I do scontrol show job <jobid>, I can spot the following output: > > NumNodes=1 NumCPUs=2 NumTasks=0 CPUs/Task=1 ReqB:S:C:T=0:0:*:* > TRES=cpu=2,node=1,billing=2 > Socks/Node=* NtasksPerN:B:S:C=0:0:*:2 CoreSpec=* > > that is each job uses NumCPUs=2 instead of 1. Also, I'm not sure why > TRES=cpu=2 > > Any idea on how to solve this problem and have 100% of the logical cores > allocated? > > Best regards, > David >
