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Timing files

Timing files#

CESM generates timing statistics for your simulation, which are important to find out the information you need to set STOP_OPTION, STOP_N, and RESUBMIT to appropriate values when running long simulations.

This chapter explains how to use the timing data to make informed decisions when configuring the variables STOP_OPTION, STOP_N, and RESUBMIT.

Location of the timing files#

Statistics of the timing of your simulation can be found in the directory timing within your case directory.

cd ~/cases/case01/timing

The location of the timing files within the CESM directories is show in Figure 1.

timing

Figure 1: Location of the timing files

Finding information in the timing files#

In the file with the name that starts cesm_timing.case01 you’ll find the following information

Overall Metrics:
Model Cost: XXX pe-hrs/simulated year
Model Throughput: XXX simulated years/day

where

  • Model Cost is the cost of the simulation in processor element hours.

  • Model Throughput is how many simulated years you can run in 24 hours.

These files are important to determine how long each submission should be.

Why is it important?#

Typically, you will run your simulations on a system with a maximum wall clock limit for each submission. The maximum wall clock limit represents the longest period (in real time) that you can run a simulation on that system in a single submission.

For instance, when you submit a run to the NCAR’s supercomputer, Cheyenne, it imposes a runtime limit of 12 hours. Ideally, you should select the longest run length that can fit within this 12-hour wall clock limit while dividing the simulation into convenient segments, such as an integer number of years.

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