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<p class="MsoNormal">Antony,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m not sure I understand your answer. I want to launch 2 tasks (managers), one per node, but reserve the rest of the cores on each node so that the original 2 managers can spawn new workers on them. Requesting 24 tasks would create
24 managers, I think.<o:p></o:p></p>
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<p class="MsoNormal">Kurt<o:p></o:p></p>
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<p class="MsoNormal"><b>From:</b> slurm-users <slurm-users-bounces@lists.schedmd.com>
<b>On Behalf Of </b>Antony Cleave<br>
<b>Sent:</b> Tuesday, December 28, 2021 6:15 PM<br>
<b>To:</b> Slurm User Community List <slurm-users@lists.schedmd.com><br>
<b>Subject:</b> [EXTERNAL] Re: [slurm-users] Slurm and MPICH don't play well together (salloc)<o:p></o:p></p>
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<p class="MsoNormal">Hi<o:p></o:p></p>
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<p class="MsoNormal">I've not used mpich for years but I think I see the problem. By asking for 24 CPUs per task and specifying 2 tasks you are asking slurm to allocate 48 CPUs per node.<o:p></o:p></p>
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<p class="MsoNormal">Your nodes have 24 CPUs in total so you don't have any nodes that can service this request<o:p></o:p></p>
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<p class="MsoNormal">Try asking for 24 tasks. I've only ever used CPU per task for hybrid MPI/openMP codes with 2 MPI tasks and 12 threads per task. <o:p></o:p></p>
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<p class="MsoNormal">Antony<o:p></o:p></p>
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<p class="MsoNormal">On Tue, 28 Dec 2021, 23:02 Mccall, Kurt E. (MSFC-EV41), <<a href="mailto:kurt.e.mccall@nasa.gov" target="_blank">kurt.e.mccall@nasa.gov</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Hi,<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">My MPICH jobs are being launched and the desired number of processes are created, but when one of those processes trys to spawn a new process using MPI_Comm_spawn(), that process
just spins in the polling code deep within the MPICH library. See the Slurm <span style="color:red">
error message</span> below. This all works without problems on other clusters that have Torque as the process manager. We are using Slurm 20.02.3 on redhat 4.18.0, and MPICH 4.0b1.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">salloc: defined options<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">salloc: -------------------- --------------------<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">salloc: cpus-per-task : 24<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">salloc: ntasks : 2<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">salloc: verbose : 1<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">salloc: -------------------- --------------------<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">salloc: end of defined options<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">salloc: Linear node selection plugin loaded with argument 4<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">salloc: select/cons_res loaded with argument 4<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">salloc: Cray/Aries node selection plugin loaded<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">salloc: select/cons_tres loaded with argument 4<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">salloc: Granted job allocation 34330<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:red">srun: error: Unable to create step for job 34330: Requested node configuration is not availableta</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">I’m wondering if the salloc command I am using is correct. I intend for it to launch 2 processes, one per node, but reserve 24 cores on each node for the 2 launched processes
to spawn new processes using MPI_Comm_spawn. Could the reservation of all 24 cores make slurm or MPICH think that there are no more cores available?<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b>salloc –ntasks=2 –cpus-per-task=24 –verbose runscript.bash …</b><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">I think that our cluster’s compute nodes are configured correctly –<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b>$ scontrol show node=n001</b><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">NodeName=n001 Arch=x86_64 CoresPerSocket=6
<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> CPUAlloc=0 CPUTot=24 CPULoad=0.00<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> AvailableFeatures=(null)<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> ActiveFeatures=(null)<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> Gres=(null)<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> NodeAddr=n001 NodeHostName=n001 Version=20.02.3<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> OS=Linux 4.18.0-348.el8.x86_64 #1 SMP Mon Oct 4 12:17:22 EDT 2021
<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> RealMemory=128351 AllocMem=0 FreeMem=126160 Sockets=4 Boards=1<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> State=IDLE ThreadsPerCore=1 TmpDisk=0 Weight=1 Owner=N/A MCS_label=N/A<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> Partitions=normal,low,high
<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> BootTime=2021-12-21T14:25:05 SlurmdStartTime=2021-12-21T14:25:52<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> CfgTRES=cpu=24,mem=128351M,billing=24<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> AllocTRES=<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> CapWatts=n/a<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> CurrentWatts=0 AveWatts=0<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> ExtSensorsJoules=n/s ExtSensorsWatts=0 ExtSensorsTemp=n/s<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Thanks for any help.<o:p></o:p></p>
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