+ (values.xStats().mean() - xStats.mean())
                  * (values.yStats().mean() - yStats.mean())
                  * values.count();
    }
    yStats.addAll(values.yStats());
  }

  /** Returns an immutable snapshot of the current statistics. */
  public PairedStats snapshot() {
    return new PairedStats(xStats.snapshot(), yStats.snapshot(), sumOfProductsOfDeltas);
  }

    assertStatsApproxEqual(EMPTY_STATS_ITERABLE, emptyAccumulatorByAddAllEmptyPairedStats.xStats());
    assertStatsApproxEqual(ONE_VALUE_STATS, oneValueAccumulator.xStats());
    assertStatsApproxEqual(ONE_VALUE_STATS, oneValueAccumulatorByAddAllEmptyPairedStats.xStats());
    assertStatsApproxEqual(TWO_VALUES_STATS, twoValuesAccumulator.xStats());
    assertStatsApproxEqual(

// RPCStats holds information about the DHCP/TCP metrics and errors
type RPCStats struct {
	Errs uint64

	DialAvgDuration uint64
	TTFBAvgDuration uint64
	DialErrs        uint64
}

// GetRPCStats returns RPC stats, include calls errors and dhcp/tcp metrics
func GetRPCStats() RPCStats {
	s := RPCStats{
		Errs:     atomic.LoadUint64(&globalStats.errs),
		DialErrs: atomic.LoadUint64(&globalStats.tcpDialErrs),
	}

	// refer https://www.kernel.org/doc/Documentation/block/stat.txt
	iostats = IOStats{
		ReadIOs:      stats[0],
		ReadMerges:   stats[1],
		ReadSectors:  stats[2],
		ReadTicks:    stats[3],
		WriteIOs:     stats[4],
		WriteMerges:  stats[5],
		WriteSectors: stats[6],
		WriteTicks:   stats[7],
		CurrentIOs:   stats[8],
		TotalTicks:   stats[9],
		ReqTicks:     stats[10],
	}
	// as per the doc, only 11 fields are guaranteed

			expMissedTasks.Value = float64(globalExpiryState.stats.MissedTasks())
			expMissedFreeVersions.Value = float64(globalExpiryState.stats.MissedFreeVersTasks())
			expMissedTierJournalTasks.Value = float64(globalExpiryState.stats.MissedTierJournalTasks())
			expNumWorkers.Value = float64(globalExpiryState.stats.NumWorkers())
		}
		if globalTransitionState != nil {

func (m *MetricValues) setDriveIOStatMetrics(ioStats driveIOStatMetrics, labels []string) {
	m.Set(driveReadsPerSec, ioStats.readsPerSec, labels...)
	m.Set(driveReadsKBPerSec, ioStats.readsKBPerSec, labels...)
	if ioStats.readsPerSec > 0 {
		m.Set(driveReadsAwait, ioStats.readsAwait, labels...)
	}

	m.Set(driveWritesPerSec, ioStats.writesPerSec, labels...)
	m.Set(driveWritesKBPerSec, ioStats.writesKBPerSec, labels...)

			return
		}
		switch msgp.UnsafeString(field) {
		case "Stats":
			var zb0002 uint32
			zb0002, err = dc.ReadMapHeader()
			if err != nil {
				err = msgp.WrapError(err, "Stats")
				return
			}
			if z.Stats == nil {
				z.Stats = make(map[string]*BucketReplicationStat, zb0002)
			} else if len(z.Stats) > 0 {
				clear(z.Stats)
			}
			for zb0002 > 0 {
				zb0002--
				var za0001 string

	}
	info.Used = info.Total - info.Free
	return info, nil
}

// GetDriveStats returns IO stats of the drive by its major:minor
func GetDriveStats(major, minor uint32) (iostats IOStats, err error) {
	return IOStats{}, errors.New("operation unsupported")

	}
	info.Used = info.Total - info.Free
	return info, nil
}

// GetDriveStats returns IO stats of the drive by its major:minor
func GetDriveStats(major, minor uint32) (iostats IOStats, err error) {
	return IOStats{}, errors.New("operation unsupported")

	}
	info.Used = info.Total - info.Free
	return info, nil
}

// GetDriveStats returns IO stats of the drive by its major:minor
func GetDriveStats(major, minor uint32) (iostats IOStats, err error) {
	return IOStats{}, errors.New("operation unsupported")