[slurm-users] [EXT] How to determine (on the ControlMachine) which cores/gpus are assigned to a job?

Thomas Zeiser thomas.zeiser at rrze.uni-erlangen.de
Thu Feb 11 19:15:12 UTC 2021


Hi Sean,

unfortunately, the CPU_IDs and GPU IDX given by "scontrol -d show
job JOBID" are not related in any way to the ordering of the
hardware. It seems to be just the sequence of the cores / GPUs
assigned by Slurm.


For reference: The PCI-IDs of the GPUs when run as root outside of
any cgroup:

| GPU  Name        Persistence-M| Bus-Id        Disp.A |
|   0  A100-SXM4-40GB      On   | 00000000:01:00.0 Off |
|   1  A100-SXM4-40GB      On   | 00000000:41:00.0 Off |
|   2  A100-SXM4-40GB      On   | 00000000:81:00.0 Off |
|   3  A100-SXM4-40GB      On   | 00000000:C1:00.0 Off |



I submitted a job requesting 1 GPU and 3 GPU to a node with 4
GPUs. Both run concurrently.


Output of the 1st 1 GPU job:

|   0  A100-SXM4-40GB      On   | 00000000:41:00.0 Off |                    0 |
SLURM_JOB_GPUS=0
GPU_DEVICE_ORDINAL=0
CUDA_VISIBLE_DEVICES=0
     Nodes=tg091 CPU_IDs=0-63 Mem=120000 GRES=gpu:a100:1(IDX:0)
/sys/fs/cgroup/cpuset/slurm_$(hostname -s)/uid_$(id -u)/job_$SLURM_JOB_ID/step_batch/cpuset.cpus=64-95,192-223

I understand CUDA_VISIBLE_DEVICES=0 as that is within the cgroup.
However, 00000000:41:00.0 is by no means IDX0; it's only the 1st
GPU assigned on the node by Slurm.
CPU-IDs do not match the cpuset in any way. (CPUs are 2x 64 cores with SMT enabled)


Output of the 2nd 3 GPU job running concurrently:
|   0  A100-SXM4-40GB      On   | 00000000:01:00.0 Off |                    0 |
|   1  A100-SXM4-40GB      On   | 00000000:81:00.0 Off |                    0 |
|   2  A100-SXM4-40GB      On   | 00000000:C1:00.0 Off |                    0 |
SLURM_JOB_GPUS=1,2,3
GPU_DEVICE_ORDINAL=0,1,2
CUDA_VISIBLE_DEVICES=0,1,2
     Nodes=tg091 CPU_IDs=64-255 Mem=360000 GRES=gpu:a100:3(IDX:1-3)
/sys/fs/cgroup/cpuset/slurm_$(hostname -s)/uid_$(id -u)/job_$SLURM_JOB_ID/step_batch/cpuset.cpus=0-63,96-191,224-255

Again CUDA_VISIBLE_DEVICES=0,1,2 is reasonable within the cgroup.
However, IDX:1-3 or SLURM_JOB_GPUS=1,2,3 does not correspond to the
Bus-IDs which would be 0, 2, 3 according to the non-cgroup output.
Again, no relation between CPU-IDs and cpuset.



If the jobs are started in reverse order:

Output of the 3 GPU job started as first job on the node:
|   0  A100-SXM4-40GB      On   | 00000000:01:00.0 Off |                    0 |
|   1  A100-SXM4-40GB      On   | 00000000:41:00.0 Off |                    0 |
|   2  A100-SXM4-40GB      On   | 00000000:C1:00.0 Off |                    0 |
SLURM_JOB_GPUS=0,1,2
GPU_DEVICE_ORDINAL=0,1,2
CUDA_VISIBLE_DEVICES=0,1,2
     Nodes=tg091 CPU_IDs=0-191 Mem=360000 GRES=gpu:a100:3(IDX:0-2)
/sys/fs/cgroup/cpuset/slurm_$(hostname -s)/uid_$(id -u)/job_$SLURM_JOB_ID/step_batch/cpuset.cpus=0-95,128-223

=> IDX:0-2 does not correspond to the Bus-IDs which would be 0, 1,
3 according to the non-cgroup output.


Output of the 1 GPU job started second but running concurrently:
|   0  A100-SXM4-40GB      On   | 00000000:81:00.0 Off |                    0 |
SLURM_JOB_GPUS=3
GPU_DEVICE_ORDINAL=0
CUDA_VISIBLE_DEVICES=0
     Nodes=tg091 CPU_IDs=192-255 Mem=120000 GRES=gpu:a100:1(IDX:3)
/sys/fs/cgroup/cpuset/slurm_$(hostname -s)/uid_$(id -u)/job_$SLURM_JOB_ID/step_batch/cpuset.cpus=96-127,224-255


If three jobs requesting 1, 2, and 1 GPU are submitted in that
order, it is even worse as the 2 GPU job will be assigned to the
2nd socket while the last jobs will fill up the 1st socket. I can
clearly be seen that GRES=gpu:a100:2(IDX is just incremented but
not related to hardware location.

|   0  A100-SXM4-40GB      On   | 00000000:41:00.0 Off |                    0 |
SLURM_JOB_GPUS=0
GPU_DEVICE_ORDINAL=0
CUDA_VISIBLE_DEVICES=0
     Nodes=tg094 CPU_IDs=0-63 Mem=120000 GRES=gpu:a100:1(IDX:0)
0-31,128-159


|   0  A100-SXM4-40GB      On   | 00000000:01:00.0 Off |                    0 |
|   1  A100-SXM4-40GB      On   | 00000000:C1:00.0 Off |                    0 |
SLURM_JOB_GPUS=1,2
GPU_DEVICE_ORDINAL=0,1
CUDA_VISIBLE_DEVICES=0,1
     Nodes=tg094 CPU_IDs=128-255 Mem=240000 GRES=gpu:a100:2(IDX:1-2)
64-127,192-255


|   0  A100-SXM4-40GB      On   | 00000000:81:00.0 Off |                    0 |
SLURM_JOB_GPUS=3
GPU_DEVICE_ORDINAL=0
CUDA_VISIBLE_DEVICES=0
     Nodes=tg094 CPU_IDs=64-127 Mem=120000 GRES=gpu:a100:1(IDX:3)
32-63,160-191



Best regards

thomas

On Fri, Feb 05, 2021 at 07:37:37PM +1100, Sean Crosby wrote:
> Hi Thomas,
> 
> Add the -d flag to scontrol show job
> 
> e.g.
> 
> # scontrol show job 23891862 -d
> JobId=23891862 JobName=SPI_DOWN
>    UserId=user1(11283) GroupId=group1(10414) MCS_label=N/A
>    Priority=586 Nice=0 Account=group1 QOS=qos1
>    JobState=RUNNING Reason=None Dependency=(null)
>    Requeue=1 Restarts=0 BatchFlag=1 Reboot=0 ExitCode=0:0
>    DerivedExitCode=0:0
>    RunTime=2-00:13:58 TimeLimit=7-00:00:00 TimeMin=N/A
>    SubmitTime=2021-02-03T19:19:28 EligibleTime=2021-02-03T19:19:28
>    AccrueTime=2021-02-03T19:19:31
>    StartTime=2021-02-03T19:19:31 EndTime=2021-02-10T19:19:31 Deadline=N/A
>    SuspendTime=None SecsPreSuspend=0 LastSchedEval=2021-02-03T19:19:31
>    Partition=gpgpu AllocNode:Sid=spartan-login3:222306
>    ReqNodeList=(null) ExcNodeList=(null)
>    NodeList=spartan-gpgpu007
>    BatchHost=spartan-gpgpu007
>    NumNodes=1 NumCPUs=6 NumTasks=1 CPUs/Task=6 ReqB:S:C:T=0:0:*:*
>    TRES=cpu=6,mem=24000M,node=1,billing=101,gres/gpu=1
>    Socks/Node=* NtasksPerN:B:S:C=0:0:*:1 CoreSpec=*
>    JOB_GRES=gpu:1
>      Nodes=spartan-gpgpu007 CPU_IDs=6-11 Mem=24000 GRES=gpu:1(IDX:1)
>    MinCPUsNode=6 MinMemoryCPU=4000M MinTmpDiskNode=0
>    Features=(null) DelayBoot=00:00:00
>    OverSubscribe=OK Contiguous=0 Licenses=(null) Network=(null)
> 
> Note the CPU_IDs and GPU IDX in the output
> 
> Sean
> 
> --
> Sean Crosby | Senior DevOpsHPC Engineer and HPC Team Lead
> Research Computing Services | Business Services
> The University of Melbourne, Victoria 3010 Australia
> 
> 
> 
> On Fri, 5 Feb 2021 at 02:01, Thomas Zeiser <
> thomas.zeiser at rrze.uni-erlangen.de> wrote:
> 
> > UoM notice: External email. Be cautious of links, attachments, or
> > impersonation attempts
> >
> > Dear All,
> >
> > we are running Slurm-20.02.6 and using
> > "SelectType=select/cons_tres" with
> > "SelectTypeParameters=CR_Core_Memory", "TaskPlugin=task/cgroup",
> > and "ProctrackType=proctrack/cgroup". Nodes can be shared between
> > multiple jobs with the partition defaults "ExclusiveUser=no
> > OverSubscribe=No"
> >
> > For monitoring purpose, we'd like to know on the ControlMachine
> > which cores of a batch node are assigned to a specific job. Is
> > there any way (except looking on each batch node itself into
> > /sys/fs/cgroup/cpuset/slurm_*) to get the assigned core ranges or
> > GPU IDs?
> >
> > E.g. from Torque we are used that qstat tells the assigned cores.
> > However, with Slurm, even "scontrol show job JOBID" does not seem
> > to have any information in that direction.
> >
> > Knowing which GPU is allocated (in case of gres/gpu) of course
> > also would be interested to know on the ControlMachine.
> >
> >
> > Here's the output we get from scontrol show job; it has the node
> > name and the number of cores assigned but not the "core IDs" (e.g.
> > 32-63)
> >
> > JobId=886 JobName=br-14
> >    UserId=hpc114(1356) GroupId=hpc1(1355) MCS_label=N/A
> >    Priority=1010 Nice=0 Account=hpc1 QOS=normal WCKey=*
> >    JobState=RUNNING Reason=None Dependency=(null)
> >    Requeue=0 Restarts=0 BatchFlag=1 Reboot=0 ExitCode=0:0
> >    RunTime=00:40:09 TimeLimit=1-00:00:00 TimeMin=N/A
> >    SubmitTime=2021-02-04T07:26:51 EligibleTime=2021-02-04T07:26:51
> >    AccrueTime=2021-02-04T07:26:51
> >    StartTime=2021-02-04T07:26:54 EndTime=2021-02-05T07:26:54 Deadline=N/A
> >    PreemptEligibleTime=2021-02-04T07:26:54 PreemptTime=None
> >    SuspendTime=None SecsPreSuspend=0 LastSchedEval=2021-02-04T07:26:54
> >    Partition=a100 AllocNode:Sid=gpu001:1743663
> >    ReqNodeList=(null) ExcNodeList=(null)
> >    NodeList=gpu001
> >    BatchHost=gpu001
> >    NumNodes=1 NumCPUs=32 NumTasks=1 CPUs/Task=1 ReqB:S:C:T=0:0:*:*
> >    TRES=cpu=32,mem=120000M,node=1,billing=32,gres/gpu=1,gres/gpu:a100=1
> >    Socks/Node=* NtasksPerN:B:S:C=0:0:*:* CoreSpec=*
> >    MinCPUsNode=1 MinMemoryCPU=3750M MinTmpDiskNode=0
> >    Features=(null) DelayBoot=00:00:00
> >    OverSubscribe=OK Contiguous=0 Licenses=(null) Network=(null)
> >    Command=/var/tmp/slurmd_spool/job00877/slurm_script
> >    WorkDir=/home/hpc114/run2
> >    StdErr=/home/hpc114//run2/br-14.o886
> >    StdIn=/dev/null
> >    StdOut=/home/hpc114/run2/br-14.o886
> >    Power=
> >    TresPerNode=gpu:a100:1
> >    MailUser=(null) MailType=NONE
> >
> > Also "scontrol show node" is not helpful
> >
> > NodeName=gpu001 Arch=x86_64 CoresPerSocket=64
> >    CPUAlloc=128 CPUTot=128 CPULoad=4.09
> >    AvailableFeatures=hwperf
> >    ActiveFeatures=hwperf
> >    Gres=gpu:a100:4(S:0-1)
> >    NodeAddr=gpu001 NodeHostName=gpu001 Port=6816 Version=20.02.6
> >    OS=Linux 5.4.0-62-generic #70-Ubuntu SMP Tue Jan 12 12:45:47 UTC 2021
> >    RealMemory=510000 AllocMem=480000 FreeMem=495922 Sockets=2 Boards=1
> >    State=ALLOCATED ThreadsPerCore=2 TmpDisk=0 Weight=80 Owner=N/A
> > MCS_label=N/A
> >    Partitions=a100
> >    BootTime=2021-01-27T16:03:48 SlurmdStartTime=2021-02-03T13:43:05
> >    CfgTRES=cpu=128,mem=510000M,billing=128,gres/gpu=4,gres/gpu:a100=4
> >    AllocTRES=cpu=128,mem=480000M,gres/gpu=4,gres/gpu:a100=4
> >    CapWatts=n/a
> >    CurrentWatts=0 AveWatts=0
> >    ExtSensorsJoules=n/s ExtSensorsWatts=0 ExtSensorsTemp=n/s
> >
> > There is no information on the currently running four jobs
> > included; neither which share of the allocated node is assigned to
> > the individual jobs.
> >
> >
> > I'd like to see isomehow that job 886 got cores 32-63,160-191
> > assigned as seen on the node from /sys/fs/cgroup
> >
> > %cat /sys/fs/cgroup/cpuset/slurm_gpu001/uid_1356/job_886/cpuset.cpus
> > 32-63,160-191
> >
> >
> > Thanks for any ideas!
> >
> > Thomas Zeiser



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