private Severity getDiskSpeedSeverity(long speed) {
    return Severity.getSeverityDescending(
        speed, diskSpeedLimits[0], diskSpeedLimits[1], diskSpeedLimits[2], diskSpeedLimits[3]);
  }
Analyzes mapper task speed and efficiency
app/com/linkedin/drelephant/tez/heuristics/TezScopeSpeedHeuristic.java