presto-verifier/src/main/java/io/prestosql/verifier/HumanReadableEventClient.java/HumanReadableEventClient/getCpuRatio
class HumanReadableEventClient:    private Optional<Double> getCpuRatio(VerifierQueryEvent queryEvent)
    {
        Double controlCpuTime = queryEvent.getControlCpuTimeSecs();
        Double testCpuTime = queryEvent.getTestCpuTimeSecs();
        if (controlCpuTime == null || testCpuTime == null) {
            return Optional.empty();
        }
        if (controlCpuTime < regressionMinCpuTime.getValue(SECONDS)) {
            return Optional.empty();
        }

        double value = testCpuTime / controlCpuTime;

        // if both are 0.0, we had no speedup
        if (isNaN(value)) {
            value = 1.0;
        }

        return Optional.of(value);
    }