Estimates the number of executors in use for a Jenkins instance

loatStatistics.groovy

def int x0 = 0;
def double x1 = 0.0;
def double x2 = 0.0;
println("Total executors")
println("===============")
println("")
println("Sampling every hour")
println("-------------------")
println("")
for (x in Jenkins.instance.overallLoad.totalExecutors.hour.history) {
  x0++;
  x1+=x;
  x2+=x*x;
}
println("Number of observations: " + x0);
if (x0>1) println("Average number of executors: " + Math.round(x1 / x0 * 10) * 0.1);
if (x0>2) println("Sample standard deviation: " + Math.round(Math.sqrt( (x0 * x2 - x1 * x1) / x0 / ( x0 - 1) ) * 10.0) * 0.1);

println("")
println("Sampling every minute")
println("---------------------")
println("")
x0 = 0;
x1 = 0.0;
x2 = 0.0;
println("")
for (x in Jenkins.instance.overallLoad.totalExecutors.min.history) {
  x0++;
  x1+=x;
  x2+=x*x;
}
println("Number of observations: " + x0);
if (x0>1) println("Average number of executors: " + Math.round(x1 / x0 * 10) * 0.1);
if (x0>2) println("Sample standard deviation: " + Math.round(Math.sqrt( (x0 * x2 - x1 * x1) / x0 / ( x0 - 1) ) * 10.0) * 0.1);

x0 = 0;
x1 = 0.0;
x2 = 0.0;
println("")
println("Busy executors")
println("==============")
println("")
println("Sampling every hour")
println("-------------------")
println("")
for (x in Jenkins.instance.overallLoad.busyExecutors.hour.history) {
  x0++;
  x1+=x;
  x2+=x*x;
}
println("Number of observations: " + x0);
if (x0>1) println("Average number of executors: " + Math.round(x1 / x0 * 10) * 0.1);
if (x0>2) println("Sample standard deviation: " + Math.round(Math.sqrt( (x0 * x2 - x1 * x1) / x0 / ( x0 - 1) ) * 10.0) * 0.1);

println("")
println("Sampling every minute")
println("---------------------")
println("")
x0 = 0;
x1 = 0.0;
x2 = 0.0;
println("")
for (x in Jenkins.instance.overallLoad.busyExecutors.min.history) {
  x0++;
  x1+=x;
  x2+=x*x;
}
println("Number of observations: " + x0);
if (x0>1) println("Average number of executors: " + Math.round(x1 / x0 * 10) * 0.1);
if (x0>2) println("Sample standard deviation: " + Math.round(Math.sqrt( (x0 * x2 - x1 * x1) / x0 / ( x0 - 1) ) * 10.0) * 0.1);