Resources Allocation Policy

Job queue policies

The resources are allocated to the job in a fair-share fashion, subject to constraints set by the queue and resources available to the Project. The fair-share at Anselm ensures that individual users may consume approximately equal amount of resources per week. Detailed information in the Job scheduling section. The resources are accessible via several queues for queueing the jobs. The queues provide prioritized and exclusive access to the computational resources. Following table provides the queue partitioning overview:

Note

Check the queue status at https://extranet.it4i.cz/rsweb/salomon/

queue active project project resources nodes min ncpus priority authorization walltime
qexp Express queue no none required 32 nodes, max 8 per user 24 150 no 1 / 1h
qprod Production queue yes > 0 1006 nodes, max 86 per job 24 0 no 24 / 48h
qlong Long queue yes > 0 256 nodes, max 40 per job, only non-accelerated nodes allowed 24 0 no 72 / 144h
qmpp Massive parallel queue yes > 0 1006 nodes 24 0 yes 2 / 4h
qfat UV2000 queue yes > 0 1 (uv1) 8 0 yes 24 / 48h
qfree Free resource queue yes none required 752 nodes, max 86 per job 24 -1024 no 12 / 12h
qviz Visualization queue yes none required 2 (with NVIDIA Quadro K5000) 4 150 no 1 / 8h

Note

The qfree queue is not free of charge. Normal accounting applies. However, it allows for utilization of free resources, once a Project exhausted all its allocated computational resources. This does not apply to Directors Discretion (DD projects) but may be allowed upon request.

  • qexp, the Express queue: This queue is dedicated for testing and running very small jobs. It is not required to specify a project to enter the qexp. There are 2 nodes always reserved for this queue (w/o accelerator), maximum 8 nodes are available via the qexp for a particular user. The nodes may be allocated on per core basis. No special authorization is required to use it. The maximum runtime in qexp is 1 hour.
  • qprod, the Production queue: This queue is intended for normal production runs. It is required that active project with nonzero remaining resources is specified to enter the qprod. All nodes may be accessed via the qprod queue, however only 86 per job. Full nodes, 24 cores per node are allocated. The queue runs with medium priority and no special authorization is required to use it. The maximum runtime in qprod is 48 hours.
  • qlong, the Long queue: This queue is intended for long production runs. It is required that active project with nonzero remaining resources is specified to enter the qlong. Only 336 nodes without acceleration may be accessed via the qlong queue. Full nodes, 24 cores per node are allocated. The queue runs with medium priority and no special authorization is required to use it. The maximum runtime in qlong is 144 hours (three times of the standard qprod time - 3 * 48 h)
  • qmpp, the massively parallel queue. This queue is intended for massively parallel runs. It is required that active project with nonzero remaining resources is specified to enter the qmpp. All nodes may be accessed via the qmpp queue. Full nodes, 24 cores per node are allocated. The queue runs with medium priority and no special authorization is required to use it. The maximum runtime in qmpp is 4 hours. An PI needs explicitly ask support for authorization to enter the queue for all users associated to her/his Project.
  • qfat, the UV2000 queue. This queue is dedicated to access the fat SGI UV2000 SMP machine. The machine (uv1) has 112 Intel IvyBridge cores at 3.3GHz and 3.25TB RAM (8 cores and 128GB RAM are dedicated for system). An PI needs explicitly ask support for authorization to enter the queue for all users associated to her/his Project.
  • qfree, the Free resource queue: The queue qfree is intended for utilization of free resources, after a Project exhausted all its allocated computational resources (Does not apply to DD projects by default. DD projects have to request for persmission on qfree after exhaustion of computational resources.). It is required that active project is specified to enter the queue, however no remaining resources are required. Consumed resources will be accounted to the Project. Only 178 nodes without accelerator may be accessed from this queue. Full nodes, 24 cores per node are allocated. The queue runs with very low priority and no special authorization is required to use it. The maximum runtime in qfree is 12 hours.
  • qviz, the Visualization queue: Intended for pre-/post-processing using OpenGL accelerated graphics. Currently when accessing the node, each user gets 4 cores of a CPU allocated, thus approximately 73 GB of RAM and 1/7 of the GPU capacity (default "chunk"). If more GPU power or RAM is required, it is recommended to allocate more chunks (with 4 cores each) up to one whole node per user, so that all 28 cores, 512 GB RAM and whole GPU is exclusive. This is currently also the maximum allowed allocation per one user. One hour of work is allocated by default, the user may ask for 2 hours maximum.

Note

To access node with Xeon Phi co-processor user needs to specify that in job submission select statement.

Queue notes

The job wall-clock time defaults to half the maximum time, see table above. Longer wall time limits can be set manually, see examples.

Jobs that exceed the reserved wall-clock time (Req'd Time) get killed automatically. Wall-clock time limit can be changed for queuing jobs (state Q) using the qalter command, however can not be changed for a running job (state R).

Salomon users may check current queue configuration at https://extranet.it4i.cz/rsweb/salomon/queues.

Queue Status

Note

Check the status of jobs, queues and compute nodes at https://extranet.it4i.cz/rsweb/salomon/

RSWEB Salomon

Display the queue status on Salomon:

$ qstat -q

The PBS allocation overview may be obtained also using the rspbs command.

$ rspbs
Usage: rspbs [options]

Options:
  --version             show program's version number and exit
  -h, --help            show this help message and exit
  --get-server-details Print server
  --get-queues          Print queues
  --get-queues-details Print queues details
  --get-reservations    Print reservations
  --get-reservations-details
                        Print reservations details
  --get-nodes           Print nodes of PBS complex
  --get-nodeset         Print nodeset of PBS complex
  --get-nodes-details   Print nodes details
  --get-jobs            Print jobs
  --get-jobs-details    Print jobs details
  --get-jobs-check-params
                        Print jobid, job state, session_id, user, nodes
  --get-users           Print users of jobs
  --get-allocated-nodes
                        Print allocated nodes of jobs
  --get-allocated-nodeset
                        Print allocated nodeset of jobs
  --get-node-users      Print node users
  --get-node-jobs       Print node jobs
  --get-node-ncpus      Print number of ncpus per node
  --get-node-allocated-ncpus
                        Print number of allocated ncpus per node
  --get-node-qlist      Print node qlist
  --get-node-ibswitch   Print node ibswitch
  --get-user-nodes      Print user nodes
  --get-user-nodeset    Print user nodeset
  --get-user-jobs       Print user jobs
  --get-user-jobc       Print number of jobs per user
  --get-user-nodec      Print number of allocated nodes per user
  --get-user-ncpus      Print number of allocated ncpus per user
  --get-qlist-nodes     Print qlist nodes
  --get-qlist-nodeset   Print qlist nodeset
  --get-ibswitch-nodes Print ibswitch nodes
  --get-ibswitch-nodeset
                        Print ibswitch nodeset
  --summary             Print summary
  --get-node-ncpu-chart
                        Obsolete. Print chart of allocated ncpus per node
  --server=SERVER       Use given PBS server
  --state=STATE         Only for given job state
  --jobid=JOBID         Only for given job ID
  --user=USER           Only for given user
  --node=NODE           Only for given node
  --nodestate=NODESTATE
                        Only for given node state (affects only --get-node*
                        --get-qlist-* --get-ibswitch-* actions)
  --incl-finished       Include finished jobs

Resource Accounting Policy

Wall-clock Core-Hours WCH

The wall-clock core-hours (WCH) are the basic metric of computer utilization time. 1 wall-clock core-hour is defined as 1 processor core allocated for 1 hour of wall-clock time. Allocating a full node (16 cores Anselm, 24 cores Salomon) for 1 hour amounts to 16 wall-clock core-hours (Anselm) or 24 wall-clock core-hours (Salomon).

Normalized Core-Hours NCH

The resources subject to accounting are the normalized core-hours (NCH). The normalized core-hours are obtained from WCH by applying a normalization factor:

\[ NCH = F*WCH \]

All jobs are accounted in normalized core-hours, using factor F valid at the time of the execution:

System F Validity
Salomon 1.00 2017-09-11 to 2018-06-01
Anselm 0.65 2017-09-11 to 2018-06-01

The accounting runs whenever the computational cores are allocated via the PBS Pro workload manager (the qsub command), regardless of whether the cores are actually used for any calculation.

Note

The allocations are requested/granted in normalized core-hours NCH.

Warning

Whenever the term core-hour is used in this documentation, we mean the normalized core-hour, NCH.

The normalized core-hours were introduced to treat systems of different age on equal footing. Normalized core-hour is an accounting tool to discount the legacy systems. The past (before 2017-09-11) F factors are all 1.0. In future, the factors F will be updated, as new systems are installed. Factors F are expected to only decrease in time.

See examples in the Job submission and execution section.

Consumed Resources

Check how many core-hours have been consumed. The command it4ifree is available on cluster login nodes.

$ it4ifree

Projects I am participating in
==============================
PID         Days left      Total    Used WCHs    Used NCHs    WCHs by me    NCHs by me     Free
----------  -----------  -------  -----------  -----------  ------------  ------------  -------
OPEN-XX-XX  323                0      5169947      5169947         50001         50001  1292555


Projects I am Primarily Investigating
=====================================
PID         Login         Used WCHs    Used NCHs
----------  ----------  -----------  -----------
OPEN-XX-XX  user1            376670       376670
            user2           4793277      4793277

Legend
======
WCH   =    Wall-clock Core Hour
NCH   =    Normalized Core Hour

The it4ifree command is a part of it4i.portal.clients package, located here: https://pypi.python.org/pypi/it4i.portal.clients