Energy

Overview

Questions

• Which two Slurm lines turn on EAR monitoring?
• Which eacct columns are watts and joules?

Objectives

• Add --ear=on and --ear-policy=monitoring to a job.
• Read POWER (W) and ENERGY (J) from eacct -j JOBID.

This episode is optional. It is the first one to drop if the room is short on time.

EAR is the Energy Aware Runtime on Snellius. The deck adds two lines to the job script:

BASH

#SBATCH --ear=on
#SBATCH --ear-policy=monitoring

and, in the script, the report switch:

BASH

export EARL_REPORT_LOOPS=1

Submit the job as usual. After it finishes:

BASH

eacct -j JOBID

Read POWER (W) and ENERGY (J). The SURF page for EAR is https://servicedesk.surf.nl/wiki/spaces/WIKI/pages/62226671/Energy+Aware+Runtime+EAR.

The course cluster does not have this tool. Use the tab.

Snellius

Course cluster

Magic Castle

BASH

#SBATCH --ear=on
#SBATCH --ear-policy=monitoring

After the job:

BASH

eacct -j JOBID

Read POWER (W) and ENERGY (J).

EAR and eacct are Snellius only. Skip the energy exercise on this cluster.

This cluster has no EAR installation and no eacct. Read the Snellius tab for the energy exercise, and skip it here.

The deck’s sample for job step 11041163-0 includes these fields: TIME(s) 56.64, POWER(W) 253.62, ENERGY(J) 14366. 253.62 * 56.64 = 14365.0368 J, which matches the ENERGY column to the nearest joule.

Challenge

Which number is joules?

In that sample, which number is POWER and which is ENERGY? What are the units?

Show me the solution

POWER (W) is 253.62 watts. ENERGY (J) is 14366 joules. 56.64 is TIME in seconds. On the course cluster, skip the live eacct job. The sample is enough to name the two columns.

Key Points

• #SBATCH --ear=on and #SBATCH --ear-policy=monitoring turn on EAR monitoring.
• eacct -j JOBID prints the report. Read POWER (W) and ENERGY (J).
• The deck’s sample lists 253.62 W and 14366 J.
• This episode is optional, and it is the first to cut. The course tab says to skip the live job.