In this document
- Accounting for Bridges use
- Managing multiple grants
- Tracking your usage
- Managing your XSEDE allocation
- Changing your default shell
Accounting for Bridges use
Accounting for Bridges use varies with the type of node used, which is determined by the type of allocation you have: "Bridges regular", for Bridges' RSM (128GB) nodes); "Bridges GPU", for Bridges' GPU nodes; or "Bridges large", for Bridges LSM and ESM (3TB and 12TB) nodes.
Usage is defined in terms of "Service Units" or SUs. The definition of an SU varies with the type of node being used.
The RSM nodes are allocated as "Bridges regular". This does not include Bridges' GPU nodes. Each RM node holds 28 cores, each of which can be allocated separately. Service Units (SUs) are defined in terms of "core-hours": the use of one core for 1 hour.
1 core-hour = 1 SU
Because the RM nodes each hold 28 cores, if you use one entire RM node for one hour, 28 SUs will be deducted from your allocation.
28 cores x 1 hour = 28 core-hours = 28 SUs
If you use 2 cores on a node for 30 minutes, 1 SU will be deducted from your allocation.
2 cores x 0.5 hours = 1 core-hour = 1 SU
Bridges contains two kinds of GPU nodes: NVIDIA Tesla K80s and NVIDIA Tesla P100s. Service Units (SUs) for GPU nodes are defined in terms of "gpu-hours": the use of one GPU Unit for one hour.
Because of the difference in the performance of the nodes, SUs are calculated differently for the two types of nodes.
The K80 nodes hold 4 GPU units each, each of which can be allocated separately. Service Units (SUs) are defined in terms of gpu-hours:
For K80 GPU nodes, 1 GPU-hour = 1 SU
If you use 2 entire K80 nodes for 1 hour, 8 SUs will be deducted from your allocation.
4 GPU units/node x 2 nodes x 1 hour = 8 gpu-hours = 8 SUs
If you use 2 GPU units for 3 hours, 6 SUs will be deducted from your allocation.
2 GPU units x 3 hours = 6 gpu-hours = 6 SUs
The P100 nodes hold 2 GPU units each, which can be allocated separately. Service Units (SUs) are defined in terms of GPU-hours. Because the P100s are more powerful than the K80 nodes, the SU definition is different.
For P100 GPU nodes, 1 GPU-hour = 2.5 SUs
If you use an entire P100 node for one hour, 5 SUs will be deducted from your allocation.
2 GPU units/node x 1 node x 1 hour = 2 gpu-hours
2 gpu-hours x 2.5 SUs/gpu-hour = 5 SUs
If you use 1 GPU unit on a P100 for 8 hours, 20 SUs will be deducted from your allocation.
1 GPU unit x 8 hours = 8 gpu-hours
8 gpu-hours x 2.5 SU/gpu-hours = 20 SUs
The LSM and ESM nodes are allocated as "Bridges large". Accounting for the LM and ESM nodes is done by the memory requested for the job. Service Units (SUs) are defined in terms of "TB-hours": the use of 1TB of memory for one hour. Note that because the memory requested for a job is set aside for your use when the job begins, SU usage is calculated based on memory requested, not on how much memory is actually used.
1 SU = 1 TB-hour
If your job requests 3TB of memory and runs for 1 hour, 3 SUs will be deducted from your allocation.
3TB x 1 hour = 3TB-hours = 3 SUs
If your job requests 8TB and runs for 6 hours, 48 SUs will be deducted from your allocation.
8TB x 6 hours = 48 TB-hours = 48 SUs
Managing multiple grants
If you have multiple grants on Bridges, you should ensure that the work you do under each grant is assigned correctly to that grant. The files created under or associated with that grant should belong to it, to make them easily available to others on the same grant.
There are two fields associated with each grant for these purposes: a SLURM account id and a Unix group.
SLURM account ids determine which grant your Bridges use is deducted from.
Unix groups determine which pylon5 allocation the storage space for files is deducted from, and who owns and can access a file or directory.
For a given grant, the SLURM account id and the Unix group are identical strings.
One of your grants has been designated as your default grant, and the account id and Unix group associated with the grant are your default account id and default Unix group.
When a Bridges job runs, any SUs it uses are deducted from the default grant. Any files created by that job are owned by the default Unix group.
Find your default account id and Unix group
To find your SLURM account ids, use the
projects command. It will display all the grants you belong to. It will also list your default account id (called charge id in the
projects output) at the top. Your default Unix group is the same.
In this example, the user has two grants with account ids account-1 and account-2. The default account id is account-2.
[myusername@br006 ~]$ projects Your default charging project charge id is account-2. If you would like to change the default charging project use the command change_primary_group ~charge_id~. Use the charge id listed below for the project you would like to make the default in place of ~charge_id~ Project: AAA000000A PI: My Principal Investigator Title: Important Research. Resource: BRIDGES GPU Allocation: 37,830.00 Balance: 17,457.19 End Date: 2030-07-15 Award Active: Yes User Active: Yes Charge ID: account-1 Directories: HOME /home/myusername . . . Project: AAA111111A PI: My Other PI Title: More Important Research Resource: BRIDGES PYLON STORAGE Allocation: 57,500.00 Balance: 12,474.99 End Date: 2019-06-15 Award Active: Yes User Active: Yes Charge ID: account-2 *** Default charging project *** Directories: Lustre Project Storage /pylon5/account-2 Lustre Storage /pylon5/account-2/myusername
Use a secondary (non-default) grant
To use a grant other than your default grant on Bridges, you must specify the appropriate account id with the
-A option to the SLURM
sbatch command. See the Running Jobs section of this Guide for more information on batch jobs, interactive sessions and SLURM.
Note that using the -A option does not change your default Unix group. Any files created during a job are owned by your default Unix group, no matter which account id is used for the job, and the space they use will be deducted from the pylon allocation for the default Unix group.
Change your Unix group for a login session
To temporarily change your Unix group, use the
newgrp command. Any files created subsequently during this login session will be owned by the new group you have specified. Their storage will be deducted from the pylon allocation of the new group. After logging out of the session, your default Unix group will be in effect again.
Note that the
newgrp command has no effect on the account id in effect. Any Bridges usage will be deducted from the default account id or the one specified with the
-A option to
Change your default account id and Unix group permanently
You can permanently change your default account id and your default Unix group with the
change_primary_group command. Type:
to see all your groups. Then type
to set account-id as your default.
Your default account id changes immediately. Bridges use by any batch jobs or interactive sessions following this command are deducted from the new account by default.
Your default Unix group does not change immediately. It takes about an hour for the change to take effect. You must log out and log back in after that window for the new Unix group to be the default.
Tracking your usage
There are several ways to track your Bridges usage: the
xdusage command, the
projects command, and the Grant Management System.
xdusage command displays project and user account usage information for XSEDE projects. Type
man xdusage on Bridges for information.
projects command shows information on all Bridges grants, including usage and the pylon directories associated with the grant.
For more detailed accounting data you can use the Grant Management System. You can also track your usage through the XSEDE User Portal. The
projects commands and the XSEDE Portal accurately reflect the impact of a Grant Renewal but the Grant Management System currently does not.
Managing your XSEDE allocation
- How do I add a user to my grant?
- How can I transfer SUs from Bridges Large to Bridges Regular (or vice versa)?
- How can I request more SUs or storage space on Bridges?
Changing your default shell
change_shell command allows you to change your default shell. This command is only available on the login nodes.
To see which shells are available, type
To change your default shell, type
where newshell is one of the choices output by the
change_shell -l command. You must use the entire path output by
change_shell -l, e.g. /usr/psc/shells/bash. You must log out and back in again for the new shell to take effect.