* cannot be <code>null</code>
* @param status {@link TaskStatus} of the completed task, cannot be
* <code>null</code>
*/
private void meterTaskAttempt(TaskInProgress tip, TaskStatus status) {
JobCounter slotCounter =
(tip.isMapTask()) ? JobCounter.SLOTS_MILLIS_MAPS :
JobCounter.SLOTS_MILLIS_REDUCES;
jobCounters.incrCounter(slotCounter,
tip.getNumSlotsRequired() *
(status.getFinishTime() - status.getStartTime()));