defer func() {
		b.signal <- b
	}()

	b.runN(n)
	// Run the benchmark for at least the specified amount of time.
	d := *benchTime
	for !b.failed && b.duration < d && n < 1e9 {
		last := n
		// Predict iterations/sec.
		if b.nsPerOp() == 0 {
			n = 1e9
		} else {
			n = int(d.Nanoseconds() / b.nsPerOp())
		}
		// Run more iterations than we think we'll need for a second (1.5x).