   print("  -c, --concurrency n: number of concurrent Dispatch blocks (default: \(CONCURRENCY))")
   print("  -n, --num_loops n: no. of times to invoke each block (default: \(NUM_LOOPS))")
   print("  -e, --effort n: no. of conversions to perform per block (default: \(EFFORT))")
+  print("  -t, --time n: maximum runtime of the test (in ms) (default: \(TEST_DURATION))")
   print("  -l, --lhs String: 1st String to be compared (default: \(LHS))")
   print("  -r, --rhs String: 2nd String to be compared (default: \(RHS))")
   print("  -ln, --lhs_num n: Select 1st string from a set of built-in strings (see below)")

var RHS:String = STRINGS[1]!

// Determines how many times each block should be dispatched before terminating
var NUM_LOOPS:Int = 1

// Debug
var DEBUG = false

import Dispatch

// Determine how many concurrent blocks to schedule (user specified, or 10)
var CONCURRENCY:Int = 10

// Determines how many times to convert per block
var EFFORT:Int = 5000

// Test duration (milliseconds)
var TEST_DURATION:Int = 5000

// Strings to be compared
let STRINGS:[Int:String] = [
