Load statistics: swarm

Load statistics keep track of four key metrics of resource utilization:

Number of online executors

For a computer: if the computer is online then this is the number of executors that the computer has; if the computer is offline then this is zero.
For a label: this is the sum of all executors across all online computers in this label.
For the entire Jenkins: this is the sum of all executors across all online computers in this Jenkins installation.
Other than configuration changes, this value can also change when agents go offline.

Number of busy executors

This line tracks the number of executors (among the executors counted above) that are carrying out builds. The ratio of this to the number of online executors gives you the resource utilization. If all your executors are busy for a prolonged period of time, consider adding more computers to your Jenkins cluster.

Number of available executors

This line tracks the number of executors (among the online executors counted above) that are available to carry out builds. The ratio of this to the total number of executors gives you the resource availability. If none of your executors are available for a prolonged period of time, consider adding more computers to your Jenkins cluster.

Queue length

This is the number of jobs that are in the build queue, waiting for an available executor (of this computer, of this label, or in this Jenkins, respectively). This doesn't include jobs that are in the quiet period, nor does it include jobs that are in the queue because earlier builds are still in progress. If this line ever goes above 0, that means your Jenkins will run more builds by adding more computers.

Note: The number of busy executors and the number of available executors need not necessarily be equal to the number of online executors as executors can be suspended from accepting builds and thus be neither busy nor available.

The graph is an exponential moving average of periodically collected data values. 3 timespans are updated every 10 seconds, 1 minute and 1 hour respectively.