HistogramExtensions.GetMaxValue — LINQ over a Hot Path

[leecampbell-codeagent]

File: HistogramExtensions.cs

public static long GetMaxValue(this HistogramBase histogram)
{
    var max = histogram.RecordedValues().Select(hiv => hiv.ValueIteratedTo).LastOrDefault();
    return histogram.HighestEquivalentValue(max);
}

This iterates the entire histogram via a full RecordedValues() enumeration just to get the last value. The HistogramBase already tracks _maxValue internally; expose it:

public static long GetMaxValue(this HistogramBase histogram)
{
    // Walk backward from CountsArrayLength to find last non-zero index
    for (int i = histogram.CountsArrayLength - 1; i >= 0; i--)
    {
        if (histogram.GetCountAtIndex(i) > 0)
            return histogram.HighestEquivalentValue(histogram.ValueFromIndex(i));
    }
    return 0;
}

Or better: the _maxValue field should be surfaced as a public/internal property (it's already maintained incrementally by UpdatedMaxValue) and returned directly. This turns an O(N) full-scan into O(1).