Dynamically adjust the process cores number – Jie Hua’s Bioinformatics Notes

Introduction

In high-performance computing or scripting environments, it’s often useful to dynamically adjust the number of threads used based on the time of day.

For example, during working hours, we might want to use fewer threads to avoid overwhelming shared systems, while at night, we can take full advantage of available resources.

This tutorial demonstrates how to use a simple Bash script to determine the current time and set the number of threads accordingly.

Bash Script

The following script uses the date command to get the current hour and then sets the number of threads based on predefined rules:

# Get the current hour in 24-hour format (00-23)
hour=$(date +"%H")

# Set thread number based on the time of day
if [ "$hour" -ge 0 ] && [ "$hour" -lt 6 ]; then
    threads=16  # Early morning: high resource usage allowed
elif [ "$hour" -ge 6 ] && [ "$hour" -lt 12 ]; then
    threads=8   # Morning: moderate usage
elif [ "$hour" -ge 12 ] && [ "$hour" -lt 18 ]; then
    threads=4   # Afternoon: light usage
else
    threads=12  # Evening: high usage again
fi

echo "Current hour: $hour"
echo "Using $threads threads"

Notes

You can customize the thresholds and thread values based on your system and policy.

This logic can be easily embedded in SLURM job scripts or any shell-based pipeline.

Conclusion

This simple method allows you to be resource-conscious and responsive to different usage patterns throughout the day. It’s a lightweight solution that works in any Unix-like environment.