When you see CPU utilization percentages exceeding 100% in docker stats, it’s typically because Docker is reporting CPU usage across multiple CPU cores. In most systems, 100% utilization indicates that a single CPU core is fully utilized. Therefore, if your system has multiple cores, the CPU percentage can exceed 100%.
For example, if you have a quad-core processor (4 cores), the maximum utilization would be 400%. This is because each core can be utilized up to 100%. So, a reading of 150% means one and a half cores are being used at their full capacity, and 600% means that all four cores are being used fully, and an additional two cores (if hyper-threading is enabled) are also being fully utilized.
Docker calculates CPU usage by adding up the usage across all cores. This approach provides a more accurate picture of the total CPU resources a container is consuming, especially in multi-core systems. If you need to monitor the CPU usage per core, you might need to use other system monitoring tools that provide a breakdown per core, rather than relying on Docker’s aggregated statistics.
